c000021a Blue screen on xp

c000021a Blue screen on xp. Every tme i attempt to start pc it goes into above error. It wont let me start in safe mode. F8 brings up safe options OK but it won't work.  I have some important files not backed up. what can I do?
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MikeKaneConnect With a Mentor Commented:
Take out the hard drive and install it as a 2nd drive in another working machine.   You should be able to browse all the files on that 2nd drive and copy off what you need.    Now this assumes that you still have a drive without massive corruption or some other sort or failure, and that the files were not encrypted using MS's solution.

Good luck.
kb5564Author Commented:
Many thanks, sound good

Does it need to be a machine with xp. and can you give me a wee bit of info how to do it or point me to where there is info
Sure,   installing a 2nd drive is very easy.    Your machine has 2 IDE or 2or more SATA channels either on the motherboard or on an add-in card.   IDE and sata are the common ways to connect a hard drive.   IDE uses a ribbon cable about 2 1/2 inches wide, the sata drive is a small cable about 1/2 inch.   You can tell which you use by looking at the current hard drive.  

Find a machine that supports your same type of connection.   Almost all current machines have IDE on board.  

If you have another machine with a single IDE drive in the primary port and a single CDRom drive in the secondary IDE port, then the easiest thing is to use the CDrom's IDE cable.  Unplug the CDROM IDE cable and use it for your 2nd drive.    Plug it in, power on, boot up, then browse the 2nd drive as d:\ (if it is working correctly).   When you are done, shut down then plug the CDRom back in.  

Here's is a more detailed explanation on how to connect a drive with alot more info than you probably want....  but make sure you understand what you are doing.   Do not re partition or reformat any drive until you get your data off!!!!!    There is no need to do it and you will definately LOSE ALL YOUR DATA



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kb5564Author Commented:
Many many thanks for taking the time to explain to a novice like me in language I understand. I can't get at it now until tomorrow morning but i'll let you know how i get on
If you have goback installed you should try the following "fix" to be able to restart your PC again:

kb5564Author Commented:
how can i do a repair install when i can't get past blue screen? even in safe mode
Ryan_RConnect With a Mentor IT Systems AdministratorCommented:
im assuming your running XP pro or any other xp version

to repair install youi need a XP bootable setup cd. Set up your BIOS so that it will try and load from the CD Drive before your C: (Each bios is different in appearance but you will generally find the bios by pressing F1, F2, F10, or the Del key just as you turn on your pc. Your looking for something like Boot options or Boot Order. Make sure CD drive is checked before hard disk drive (HDD) and save setup and exit.

Insert the xp cd and and restart the pc, the pc should boot from the disk (you may need to repsond to the prompt "Press any key to boot from CD". Since your pc will bopot from the files on your cd it doesn't matter how corrupt your installation is on your HDD. After the setup program loads all the drivers down the bottom of the screen, you will be presented with 3 options (i should know this off by heart the amount of times ive donw this recently). You have 1) install xp, 2) launch recovery console, 3) quit. Choose opt 1

On one of the next screens you have 2 more options: 1) fresh xp install (to format partition or use a spare one to install xp 'brand new'), 2) To repair windows. Select opt 2 by pressing 'R'

Then just sit back and relax, setup will delete current system files and replace with the ones on the cd. you will need the correct XP Key/serial to finish the repair, i'm unsure if you need to activate windows again however. If your xp cd doesn't have SP2 slipstreamed into it you will need to reinstall SP2 + all other updates that youve downloaded. All your programs, docs, and drivers should remain instact. However there are a few programs that you may need to reinstall (depending if you use them). In my case, i need to reinstall Virtual CD v5 so that it can recreate a virtual drive on my pc to use my virtual cds. more info on that later upon request.

as you can see you don't need to worry about being able to boot xp to repair it.
i think win 2k also has repair function but never really used it.

Note: After you run the first phase of xp setup, the pc will restart automatically in 15 secs, when it restarts don't boot from cd again (or you repeat what youve just done) instead just ignore the prompt to boot from cd and let it boot from HDD. Setup has already changed your HDDs settings to start up the next phase of xp setup not your old corrupt version of xp

hope this helps you, kb~~
Ryan R
kb5564Author Commented:
This is very clear and very helpful, but i can't find a "XP bootable setup cd". Can i download it or is this any good, which can be downloaded "Windows XP Home Edition Utility: Setup Disks for Floppy Boot Install"
Ryan_RIT Systems AdministratorCommented:
you will need some sort of XP setup cd for this procedure to work. if you have one that is not bootable (like xp home perhaps) you could use floppy boot disks to start xp setup.

insert a blank floppy disk into your a drive.
goto my computer, right click the A drive icon and choose Format. In the dialog that appears check the "Make Windows Boot disk" or whatever it says

then apply what i said last about changing the boot order in the bios so that your floopy disk is first. Insert the floppy disk before your pc restarts and try to use the floppy disk you made to access and run the setup off your xp cd.

you cannot download an xp setup cd (not legally anyway). any friends that might let you borrow their cd (ask if it is a corporate one, as you will not be able to activate the key on that disc if your friend has already done it.) a corporate cd will have one (or more) serial keys that you can use and will not ask you to activate within 30 days after the repair or fresh install is complete. you won't be able to run setup programs from microsoft that check if your OS is genuine however.

if you find a cd and opt to use the floppy disk method but cannot use the disc to start setup, could you tell me exactly what happens when you boot from the disk (i would check myself but i don't have a floppy drive in my pc, never use it)

Ryan R
You need an XP CD of the exact version you have installed, if it is an OEM version, you also need the OEM version of the CD, or the repair installation won't work. Anyway, did you have goback installed like I mentioned in my earlier post, because that could have caused the problem in the first place.
kb5564Author Commented:
I have taken out hard drive and put in an older pc as secondry drive and am able to see it (as Mikekane suggested).
There were 5 users on my PC (xp home by the way) all family.   When i saw the hard drive 4 users are showng as 0 bytes and appear empty and yet my youngest daughter has all her file intact. It's an 80Gb HD and we had approx 65Gb used, mostly mine. Now strange thing is that when I go to properties on my HD it's still showing approx 65Gb. Do you think files are likely to be there - if those are gone then I don't have to worry about losing stuff.

Anyway when I put it back into my pc it still won't start even on safe mode, with same message and blue screen

making the floppy start up disc? do i need to use the hard drive of my problem pc above or can i use my laptop - also xp home - and does the floppy start up replace the cd?

I'm pretty sure i don't have goback installed - but i should have checked when i had it as secondary drive - i'll try and do that tonight
Ryan_RIT Systems AdministratorCommented:
have you recently installed any service packs or have you done anything recently that might cause this stop error?

how noisy is your hard drive when your turn on your pc? New HDDs are very quiet. When your HDD starts to make some noises and you can hear it spinning it's a good idea to backup your important files. Happened to me once.

 common problem for this error is installing SP1, but there are quite a few others: http://search.microsoft.com/results.aspx?q=c000021a+Blue+screen+xp&l=1&mkt=en-US&FORM=QBME1

i woulkd backup whatever files you have been able to recover at this stage by slaving your HDD. It's is possible that your files have been corrupted, maybe an incorrect shutdown while some of your files were open and being written to.

let me know what you find out - will probably check back here in 2 hours and then 4 hours after that
GinEricConnect With a Mentor Commented:
You need to first state the make and model of your motherboard.

Someone said most boards have an IDE slot, and somewhere else that they have two.  However, some motherboards have three IDE slots and unless the drivers are proper you won't be able to install things like XP, which will see double vision on the drives and they will get confused.

After the make and model, you need the full error report; put it in the computer where you can read the files and look for the dump file, probably under Windows or Windows/System32

You need to know what the full error is, but since it works in computer B, but not in computer A, it's pointing to the motherboard and its drivers, IDE slots, and so on, in computer A.

It seems you're trying to reinstall XP on a system in which it's not going to reinstall.

All you really need to reinstall XP is the i386 directory on any CD, from the XP install CD.  That's because everything is there, from the winnt.exe or winnt32.exe setup to all of the files necessary to install.  You can even copy these to the hard drive you're talking about, put it back in the machine, get to safe mode and a command prompt, and run winnt.exe /? which will tell you how to install bootless and without creating an emergency floopy disk, something like

winnt.exe /s:C:\i386 /b

Before you get to someone suggesting the fix mbr and/or formatting, you might want to try this and to state the motherboard make and model, just to see if it's the number of IDE slots that are interfering.  It could just as well be that you have the jumpers wrong on a CD drive.

Otherwise, the error suggest you have some corrupt system files somewhere because you never scandisked or defragged the drive and probably never moved [resized] the disk cache.  Bits do wear out over time on disk, believe it or not.

One corrupt system file and you probably would get a crash.

You can also try to resize the pagefiles, but carefully, and then restore them.  Be aware that if you do this from a different system, XP might not like it when you try to boot up into the old system.

Ryan_R suggestion to back or copy the files you need is the best one.  Then you can try the other tricks.  I doubt that the hard drive is bad, most likely it's corrupt because certain areas have not been re-written lately, like the system areas and perhaps the disk cache.

You should do the chkdsk scandisk and defrag at least once a year, and move the disk cache around at least as frequently.
Ryan_RIT Systems AdministratorCommented:
On a typical motherboard from 4 years ago or more you will see what looks like 3 IDE slots. 2 are for your HDD's and optical drives (CD/DVD), the 3rd one is smaller and is used only for your floppy drive (3 1/2 ")

Booting up XP is a very fine-tuned process. it only takes one small file to be missing or replaced by an incorrect version of it for the whole system to crash. That's why you need to do a repair as it will replace all of your system files (back to XP without any service packs (unless they are slipstreamed on CD)) leaving your documents and program files intact.

have you created the floppy boot disks? you can do this on any computer running XP. WARNING: do not get boot disk files from the net. They could contain all sorts of viruses that will further wreck you pc. Insert the black disc into A: and run the format A: utility in XP.
did you check the links i provided (including the other links in the answer to the EE link)?
if you don't have an xp cd per se, do you have a recovery cd?  do you have a recovery partition (check manual or mfg website on your make/model)?
kb5564Author Commented:
Situation has changed a wee bit

But first, i should say this is my first time on this site. what should i be doing re. point value etc. I am finding the help invaluable. Don't know how i can repay you're patience.

I found the xpinstalation disc - yes you guessed it - it was in the cd drive since the start of this episode, but i didn't know how to engage it and forgot i put it there

anyway, done an xp repair following instructions above. Now i have no blue screen error. But on start up it gets to normal "windows is starting up" and no further - then after about 2mins it reboots and does it all again. safe mode is no help

PS i couldn't give it "2000 pro" wen it asked during repair (can't find it agaain) but it didn't seem to mind
Ryan_RIT Systems AdministratorCommented:
you know us experts will do ANYTHING for points, right?

that is a bummer that startup is still failing. i'll think about it while i answer some other questions and hoepfully get back here soon

Ryan R
Ryan_RIT Systems AdministratorCommented:
ok i'm back and haven't thought of anything yet (think brain think)    :-)
Ryan_RIT Systems AdministratorCommented:
what was the last thing you did before the initial error appeared?

did you install a program that altered or created files in the system directory  like BootSkin.exe for example
although the xp repair fixes bootskin.exe's potential damage

so the system restarts by itself after 2 mins or you get bored and restart?

boot safe mode, look at all those lines that appear and tell us what the last line says (or what the last driver loaded is)

will be back soon, have to change classrooms now
Ryan_RIT Systems AdministratorCommented:
i can't help you until i get more info on your problem
will check back here later
try booting into safe mode command prompt & run the system restore program, select a date prior to when this occured
Ryan_R, I have a few brand new socket 939's that have three full sized IDE slots on servers, and two others, 754 and 458 or something, on workstations.  Dell and HP for the workstations.  They all have the same problem, they don't see that third slot correctly even when XP is installed, and HP and Dell are monstrous about it because they have image restore partitions that know this, but you need the restore CD sets once you do something as silly as format the hard drive.

Oh, and in addition they have two floppy slots, the smaller ones, and some have two or three SATA and/or PATA slots.  They are not from 4 years ago, and the IDE Slots are definitely full sized IDE slots.

Windows treats IDE as SCSI, using the same .sys file for both.  If Plug and Play gets hold of the Interrupt Lines 14 and 15, or, screws with the IDE reserved legacy slots in the BIOS, these will all behave unpredictably.  It's a silly thing, but IDE is not SCSI and a CD ROM is not a DVD.  Yet Windows programmers use the same drivers for all of them.  This leads only to major driver problems and drives being seen incorrectly.  Add to that the auto sense of Master and Slave drives, and it becomers a nightmare.  One should always set the jumpers on all drives, preferably one at a time, rebooting each time at least into the BIOS setup to make sure the BIOS sees all drives correctly, before trying to install Windows to a new or even a recently formatted system.  PnP in the BIOS generally should be shut off because that setting allows the BIOS to take over the Plug and Play and Windows doesn't like that; Windows wants control of the Plug and Play.

Now, he didn't say how he got to this problem.  Was it a running system that suddenly went haywire, or was it a new motherboard or a new addition of a drive, hard drive, CD, or DVD?  If the first sentence of this paragraph is true, then something went wrong to cause the problem.

What can go wrong on a working system to cause one to lose the disks?  Disk cache and system areas that have either been corrupted or simply lost some bits owing to entropy and hysterises losses on the disks over time.  Magnetism decays over time and causes disk corruption which causes errors, sectors being marked as bad, but only if the operating system can detect and handle the errors.  If the error occurs in the area where the detection or error handling itself is on disk, as well as any other critical system area, then the system cannot recover from the error and it simply crashes time after time.

The motherboard drivers, or at least those necessary to work the disks, exist on the disk if XP was already installed and running.  If the Operating System went bad, then he may not be able to repair or reinstall.

The key was he said he had moved the hard drive to another system and was able to read the data he needed.  At that point he should have captured all of that data and decided what to do next.  The obvious thing was to "recondition" the hard drive by exercising it, that is, writing to all areas of the disk.  You can only do this if you can write to both the system areas and the pagefile areas, all hidden files, all read only files, etc.. You must exercise the write head on the entire disk to recondition it.

Get the files off the disk by copying them, however you can accomplish that.  Myself, I would format the whole drive three times to make absolutely sure it is back to a state where all writes and reads will work for the next few years.  But I would get all the data I needed off of it first.  I've done this quite a few times.  It happens mostly because people never exersie the disk about once a year, and Windows doesn't do it either.

If, after formatting and making sure the BIOS sees all drives correctly, XP still won't install and it dies out with that error, then it's safe to figure that the disk has finally had it.  At this point buying a new disk is a good idea.  But when you go to install something like Winodws XP, don't just install it on a great big 200 to 300 meg partition, i.e., the whole hard drive, but partition it into at least 100 meg partitions and install to the first partition.  No sense in losing everything again in the future because good partitioning and planning was not implemented from the start.

Some reading on this is here: http://www.Musics.com/manhtml/Windows/Partitioning/PartitioningWindows.html

You can also simply browse the files given by the links there.

For the supertech: http://www.Musics.com/manhtml/Windows/Disk/Recovery/DiskRecovery.html

Electrophysics of why disk becomes corrupt: http://www.musics.com/manhtml/Windows/TwilightZone/ProcedureCrashFix.html#Procedure

What is the "Charlie 21A" error precisely?  Error #538 in the Virtual Space Charlie.

Error #538 may be an assembler message, compiler message, or installer message: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/devinst_d/hh/DevInst_d/troubleshoot_836ef6f8-9331-4228-8b49-65484adef442.xml.asp

And these are all related: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xpehelp/html/xetbserrormessages.asp

Those are about the most technical documents you can find on how these error messages are generated.  Unfortunately, no one seems to have a simple listing of the Error Codes by hex number or decimal number, but these numbers haven't changed all that much for nearly 40 years now and they're all based on old time mainframe error code reporting.  It can get even more technical as each bit is assigned an actual hardware error bit.  But of course it's easier to troubleshoot for someone who knows these bit codes.

The poster of the question obviously just wants to get his system fixed.  But sometimes you just need some convincing evidence that the real problem may have been overlooked, and some good advice on what to do about it.  That advice is to save the files you can by reading them with the drive in another system.  And then try whatever you can to recondition and reinstall the Operating System.  And you have to do it one step at a time with a little reading about how to redo a system that has failed.

It would help everyone here if he would state the motherboard make and model, what he was doing before it failed, did he set the hard drive and CD driver jumpers correctly, and what are the critical BIOS settings and reports.

The points are unimportant.
kb5564Author Commented:
I was having virus problems. there had been no up to date virus protection for about a year.
I was trying to do a http://housecall.trendmicro.com/ online scan but it kept stopping halfway through so i purchased online  norton  and was trying to download when everything went pairshaped. it wasn't an instant crash rather things got progressively worse over the half hour i was trying and retrying to download norton

it's a 2year-old dell

last line on safe mode
try hooking it back into that other computer, boot from that computer's hard drive into safe mode, then have it run a full virus & spyw scan on your slaved drive

also as was mentioned earlier, while slave to another computer, backup your files in the event you need to wipe the drive totally, format, & reinstall from scratch
first did you try this or not?:

try booting into safe mode command prompt & run the system restore program, select a date prior to this issue
kb5564Author Commented:
all above tried

scan done, but it was not up to date norton - does that matter

can't get the files that are important as mentioned earlier - "I have taken out hard drive and put in an older pc as secondry drive and am able to see it (as Mikekane suggested).
There were 5 users on my PC (xp home by the way) all family.   When i saw the hard drive 4 users are showng as 0 bytes and appear empty and yet my youngest daughter has all her file intact. It's an 80Gb HD and we had approx 65Gb used, mostly mine. Now strange thing is that when I go to properties on my HD it's still showing approx 65Gb. Do you think files are likely to be there - if those are gone then I don't have to worry about losing stuff."

also have tried earlier date in safe mode - still no joy

If they files are there, even if they were deleted, finding them is the problem, then recovering them.  The whole thing about diskprobe at http://www.Musics.com/manhtml/Windows/Disk/Recovery/DiskRecovery.html can be used to subsitute any filename or phrase that you remember, even down to any content you remember, to find the file, even if it's been deleted.

You must do this with the hard drive installed basically as a read only disk in another system.

It's a tedious job too, finding and verifying that you have the file you're looking for.  Doing it for multiple files is time consuming.

I'd bet the files are still there.  Getting them back is not going to be so easy though.
kb5564Author Commented:
I read this on another site

he mentions Trend virus software which i had been trying to use just prior to the problem

"Hi there. I am a PC Tech and have come accross this several times.
The main cause of this, is BIOS level virus protection. Mostly Trend Chipguard. What this does, is prevent changes being made to the MBR (Master Boot Record)
To stop this from happening, you will need to go into your BIOS and turn off bios protection. (Or simply restore defaults. This feature is NOT turned on by default, for a very good reason.)
It can also be caused when upgrading if you have multiple UNC protocols installed, for example Client for Novell Networks.
If this is the case, booting to the recovery console and typing disable MUP will work. If caused by bios virus guard however, this will do nothing. An update writes to the MBR saying do this before you next restart, but if this sector is protected, this can not happen - therefore, stall."

Is this worth a try and how do i do it. I can get into what i think is bios following your earlier instructions and usng f2, but the dosen't seem to be the necessary option

Ryan_RIT Systems AdministratorCommented:
Some of you guys must have sore fingers by now, still i reckon it's sometimes easier to type more than it is to read more.

This question is starting to get very technical and i think there are some issues with the way Dell or HP had previously set up the PC before you tok action to fix it. When you get a PC off the shelf (ie a Dell, HP, Compaq PC with an OS already loaded) it's usually best to create a backup of the system before you start installing extra stuff and putting on your documents. They sometimes have special partitions containg drivers, etc.

You're best bet is to get everything you can from your HDD and burn it to DVD or whatever else you can do, format the HDD and just start again. If your HDD is making some noise (you can easily hear it spinning more than what it used to ) it would be a good idea to get a new one. At least if you got a new HDD you wouldn't need to format the other one and you would have more time to find an answer as to why xx gig of your docs is missing.

when you open the '0 bytes' folder on the other PC, do you still see all the folders in there without the files?
ie You can get into C:\Docs and Settings\username\Local Settings\Temp or do those extra folders not exist as well.
it's possible you can't see them pretty much because a virus deleted them. sounds like something impossible at first but in reality it's not. we once had a virus that did the opposite. copied all of our docs from C:\Docs & Sets\Mike to C:\D & S\Administrator so that we ran out of HDD space.

It's a pain starting again but you may just have to. Sorry I couldn't be of more help to you.
kb5564Author Commented:
You have been tremendious help. THis has been a steep learning curve for me, but with you guys help a complete novice has learnt a whole lot

Anyway big change to the situation (and maybe i ommitted to say the folders showing 0butes were all complete users who had passwords to get in. when i used treesize pro, which was on the other pc, I could see they were there but still had access denied

I found this on another site - (probably stuff you know, if i had only gave you enough info)
"To take ownership of a folder:
Right-click the folder you want to take ownership of, and then click Properties.
Click the Security tab, and then click OK on the Security message (if one appears).
Click Advanced, and then click the Owner tab.
In the Name list, click your user name, Administrator if you are logged in as Administrator, or click the Administrators group. If you want to take ownership of the contents of that folder, click to select the Replace owner on subcontainers and objects check box.
Click OK. The following message appears, where folder name is the name of the folder that you want to take ownership of:
You do not have permission to read the contents of directory folder name. Do you want to replace the directory permissions with permissions granting you Full Control?
All permissions will be replaced if you press Yes.
Click Yes.
Click OK, and then reapply the permissions and security settings that you want for the folder and its contents.
back to the top"

anyway, hey presto. I have got my important files trasfered to other pc

On your last point, my hard drive is not noisy so i'll follow your advice on reformating.

I'll let you know how i get on

PS still don't know what i'm expected to do with points - but you deserve a bucket load
Do whatever you want with the points, it's not really why most of us are here.

Now check all the files with a good antivirus scanner on the other computer!

Good job.
Ryan_RIT Systems AdministratorCommented:
i concur with the 0bytes refferring to the password protection. Especially since most of the 'young daughter' users don't have password protected accounts.

sometimes using google  return better results than we do, sometimes we forget the easiest of questions.

I'll let you celebrate the recovery of your files. It seems GinEric doesn't want any points (Hint Hint)    ;-)
well now that you've gotten your files backed up to another computer

it is time to wipe this drive & reload the o/s (be sure to delete the old partition first)

Ryan_RIT Systems AdministratorCommented:
if you've already done a repair install of XP, doing the fresh one is almost exactly the same, except you keep pressing enter instead of R and follow the prompts for formatting the HDD or to delete / create partitions. You will need to download and reinstall all the updates again including SP2 if it's not slipstreamed. Sorry to Friar Tuk if your links cover this. I can't acess them at school. Let us know how you go.
tis ok, those links show graphics step by step to make it easier
Last minute reading before you partition a newly formatted drive:


no need to go through installing DOS, win3.1, etc., but do separate, if you can, Operating System on one disk or partition, Users & Applications on another, and finally Databases on another; you can also put the applications on another or wherever you decide.  Doing it this way will save your data the next time you have a crash or problem.
split to all for providing lots of help - per user's last stmt in last comment on 7/9 "you deserve a bucket load"
Ryan_RIT Systems AdministratorCommented:
no obj's - thanks rindi
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