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isapnp.sys Pause into safemode

sorush asked
Last Modified: 2012-08-14
I have a laptop windows xp home. genuine.
Can not bootup normally into xp. Trying to boot into safemode loads everthing upto isapnp.eys.
Removal and replacement of the file doesn't do anything.
I have used the expand command in recovery console. How do I find out what windows is trying to load next. and resolve the issue.
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kaskhedikar_tusharTechnical Manager


- Can you check with system restore?
- Repair your windows XP.

Tushar Kaskhedikar  
The file pciide.sys is loaded after isapnp.sys . You can expand it the same way you did isapnp.sys:

Also check the c:\windows\system32\drivers folder for any *.sys file of 0kb size. If there are, delete them.

Finally, once you're able to boot into Windows again, run a virus scan, as these files could've been corrupted by malware.


I haven't been able to sort out the problem. Safemode loading sill pauses at isapnp.sys. What can I do?
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I have replaced isapnp.sys and pciide.sys using expand in recovery console. I don't have the original windows xp cd that was used. But I do have an alternative. I do have the folders I386 and valueadded in the C: drive.
Why would I have to recover the registery files from the system restore. And I don't have the original cd to restore. However I do have an alternative windows xp cd home and on the laptop there is a certificate sticker.
Why would I have to recover the registery files from the system restore[?]
It's possible that malware or some other program inserted some driver file between  isapnp.sys and pciide.sys in the registry, and Windows is looking for this different missing or corrupt file. Or it could be some other registry issue. By restoring the registry to a previous state, you hopefully restore it to a point before the problem occurred.

I don't have the original cd to restore. However I do have an  alternative windows xp cd home and on the laptop there is a certificate  sticker.
You don't need the original install CD to do a repair install. As long as the laptop is running XP Home, than your XP Home installation CD should work fine. Just be sure to follow the instructions in the link I provided above carefully, as you want to be sure to do a repair install and not a clean install.


Will repair installing case windows to reinstall and ask me for a windows key. Which are obviously different from the one installed.


With the windows repair install, I've ended up at the windows installation screens and the usual 39min to install. I though you said that that would not happen. I'll be lucky if I'm not asked for a serial.
A repair install overwrites almost all the system files with the originals from the CD, so the install time does take about the same as a regular install. The installation does look a lot like a regular install, although it may skip some steps. It doesn't overwrite the registry (at least, not all of it), and doesn't change the Documents and Settings folder, so your user account, programs, and files will still exist. It also doesn't ask for an activation key, since one already exists on the current installation, and it doesn't overwrite that information.


marsiles, the repair install I did has asked to give the windows xp key. I still seem to have all the registery files etc as the boot up into safemode is still giving me an isapnp.sys pause. I am going to restore the registery as you mentioned. But do you think there is anything I have done wrong that has resulted in being asked cd key?


In regards to using the manual procedure to system restore , I have found a program ERD system restore to restore the computer back to origianl state, I have restored it to back to 3rd september but its no good, so now I'm going to restore it back even further.


I managed to replace all the registry files with the oldest reg files. However after that I logged into windows in safe mode which took a long time to load. I logged into the user name and the password worked. But I couldn't see any of the usr files on the desktop, and in the documents and settings I couldn't find anyother users that had files as documents and settings.


Now the windows activation is not allowing me to login until I activate windows.
I'm pretty sure you should be able to Safe Boot and log into Windows, even if the regular boot is complaining about activation. Safe Boot doesn't load the activation check.

To get Windows re-activated, use the activation key on the side of the computer. You may need to call into Microsoft to have them give you an activation code, as the online activation may not work.

If you're able to run system restore to previous dates, it sounds like you ran a repair install, but you shouldn't be missing your files. Sometimes when something goes wrong with a user account, Windows will create a new folder and start the account from scratch. The original account's folder should still be in the Documents and Settings folder though. Typically the new account folder will have the same name as the old account folder, but with a ".001" appended to the end.

List all the folders that you have in the Documents and Settings folder, and let us know which one is the account you log into that's missing the files.


I have tried to run windows in safe mode. The first time I did this I was able to log into safemode and saw that the files were missing. Now I'm going to activate windows so that I can gain access to windows and sort out the problem.


What about key changing programs, I have one here and I wanted to change the windows key to the one on the xp lable, Do I have to change the product ID and PID?


I can't see the user there. I have
All Users
Default user
LocalService. NT AUTHORITY
NetworkService.NT AUTHORITY

The name of the user is Louisa.
There isn't any folder. For it.

I restored the registery manually back to some time in June.

What should I do?


When I try to login to normal mode I get the message that do I want to activate windows now. When I click yes the HDD flashes activity but nothing load for me to activate windows.
It sounds more and more like you did some other type of install of Windows other than a repair install. It's possible you did an install over the original Windows install instead.

First, you should probably stop using Windows on the PC right away. If your files were deleted by the re-install, the more you use the computer, the less data you'll be likely to recover.

Ideally, you'd want to take the harddrive out of the current PC and mount it as a secondary drive on another PC (either internally or externally). If this isn't possible though, you can use boot CDs like ERD or UBCD4Win, or a Linux LiveCD like Parted Magic on the PC instead.

Check the following folders for your files:

They're really the only to folders you listed that could hold your user account. Note that the folder name doesn't have the match the name you use to login.

If you can't find them anywhere on the drive, you'll have to run a file recovery program. Have the recovery program scan the drive and see if it finds any of your files. If it does, have the program recover the files to a separate drive. Do NOT recovery files to the same drive you're recovering from; most recovery software will warn against this anyway.


I can distinctly remember that run the repair install. A number of files were deleted a lot were installed. I was just really hesitent but since you said nothing should go wrong I did it anyways. I'm running active undelete and it is going to run the scan for a number of hours maybe upto 7 hours. But I am in safe mode at the moment.  I have an external hdd that will use to backup the data.
A proper repair install should not touch the files in the Documents and Settings folder, but it's not without risks, which is why I recommended restoring the registry files before trying a repair install. Also, the repair install guide I linked to listed several warnings about the procedure, which I hope were heeded.

Why are you using Active Undelete? Was that a program you already had on hand? The three boot CDs I listed each included file recovery programs.

Why is the scan going to take so long? Did you select to do a quick scan? What's the capacity of the drive?


The capacity of the drive is 80GB, and I'm using a boot cd that has that program on it. I did a full scan which program would you recommend.
I was curious about Active Undelete because it's not on the discs I mentioned, and there doesn't appear to be a free version of it. However, I'm sure it works fine.

According to Active's site, a quick scan should've worked fine, and is what they recommend for recovering most files:

A low level scan should likewise discover the deleted files, but the scan could take longer.
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