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Diagnosing a very slow XP computer (startup and intermittent 100% CPU)

snatchman85 asked
Last Modified: 2011-10-03
My friend gave me his computer to take a look it.  It's a Dell Demention 4600, about 3 years old.  When I first tried starting it up, it got hung up on the Windows XP loading page, and never actually got to the desktop.  I tried to run it in safe mode, but would get hung up also and never got there.  So I pulled the HD out, put in into one of my other computers, and it was in bad shape.  I was able to extact most of the files from it, but I decided to put a new HD in the Dell to see if that was the problem.  After putting in the new HD and formatting it with XP Pro, there was still a hangup at the loading screen and the progress bar was moving very choppy like, but eventually (1-1.5 min. later) it would reach the desktop.  Then, as I started navigating through windows, I realized it was very slow going.  So I opened up the task manager, and the CPU was pegged at 100% with explorer.exe at around 70% of it.  It would drop off a little bit occassionaly, but usually it's pegged out - even with no applications running whatsoever.  I disabled the modem and sound card to see if those were causing the problem, but no dice.  The HD is brand new, and I haven't connected it to the internet, so spyware/malware isn't an issue.  I haven't loaded any programs on it.  I'm thinking it's got to be a hardware problem.

So, any suggestions or procedures I should do to figure out what's going on?  Does it sound like a CPU or motherboard issue?  Any other hardware?

Thanks for the help!

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Top Expert 2005

Well maybe a RAM issue.

You could try a linux live CD and check if the problem still persist.

I suggest you use http://www.knoppix.org/

KNOPPIX is a bootable Live system on CD or DVD, consisting of a representative collection of GNU/Linux software, automatic hardware detection, and support for many graphics cards, sound cards, SCSI and USB devices and other peripherals. KNOPPIX can be used as a productive Linux system for the desktop, educational CD, rescue system, or adapted and used as a platform for commercial software product demos. It is not necessary to install anything on a hard disk. Due to on-the-fly decompression, the CD can have up to 2 GB of executable software installed on it (over 8GB on the DVD "Maxi" edition).

Hmmm, quite a surprise to read this.... Iv been working on a computer with simular problems earlier.

 From what i could see from that PC, was that the amount of RAM memory was to low to boot Windows XP. XP needs AT LEAST 128 mb of ram to boot. Many of these older PC`s dont meet that criteria. Please notice that the 128 mb ram is OS only. If any other programs boot along with it, the amount increases. What happends is that the computer will try to load the OS(Operating System), but gets out of resources while doing so. It works like this: The RAM is filling up, so there is no more space for the additional data. To make space, the computer puts some unused RAM(least accesed) on teh harddisk, and uses the free space to load the rest of the data it needs. However, when the data it previously stored on the harddisk is needed again, it had to swap it with the ram again. And what do we get then? then RAM is totally full, and begins to fail to deliver the data thats needed(its desperatly trying to get all the required data in the RAM, but some critical data is also on the harddrive, and it cant be switched, since the RAM is also full of critical data)

Im thinking this is the problem, since you also said the harddisk is in very bad shape. If the HD has to endure this kind of workload each time the computer starts, and also when your working on it, it will have quite some inpact on the stability of the drive.

I cant be sure this is the problem however. Do you have any idea how many RAM is in the PC.

To give a solution if this is the problem: Buy some additional ram to make sure you have at least 128 MB (and i advise 512 for smooth operation). You can also deinstall windows XP, and go for an older breed of windows like 98. However, i should do that as a last chance option


Thanks for the suggestions.  I don't think RAM is the problem, as the computer has 1 GB of RAM in it.  Unless it is corrupted?  I probably should have put these specs in the original post:

Pentium 4 - 2.8 GHz

try stress testing the ram
Top Expert 2005

with ram issue I didn't mean too little momory but rather malfunctioning.

As said, you could give that knoppix CD a try. It comes with a ramtest in the bootmenue.


pc world magazine recommends this gnu program

Hmmm, that should indeed be enough ram.
Can you try to boot the PC in safe mode? Just before the loading page displays, hit F8. This should get you in a menu. In this menu, select: Boot in safe mode.

When you did this, let the PC boot and see if it still boots very slow. While i think its indeed a hardware issue, i want to be sure the OS itsself isnt the cause of it.
First i would check the bios and make sure compatibility mode isnt turned on, if thats not the case i would run full diags on the system using your resource cd that shipped with the system just boot to that cd and choose diagnostics the extended diagnostics



Great suggestion - did a full diagnostic and got a major error with the primary cache.

Device: L1 Cache
Test: L1 Data Cache Pattern Test

Error Code - 0700:0120
No cache detected, cache may be disabled, defective, or not present

Then immediately after that:

Device: L1 Cache
Test: L1 Data Cache Walking Bit Test

System error!
Msg: SYSTEM_ERROR Illegal attempt to disable IntellCH SMI without resetting orignal values first

Suggestions?  Is the RAM shot, or is it more serious?

And no, it doesn't have a warranty - so is there anything I can do to fix it?

Thanks again fellas!
l1 cache is on the cpu so its either the motherboard or cpu that bad, most likely the cpu
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Top Expert 2005
This one is on us!
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For me its hardware problem but it’s not RAM issue
Can you try this? Put your finger inside the fan I mean CPU fan and check if you can stop it don’t press hard little bit if yes try to clean it and put some little oil inside
If no big deal try to replace it

Try to update this entry in the Registry of Windows Xp the Key is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\PrefetchParameters
and the entry is   "EnablePrefetcher"  its value is  "3"   make it  "0"  and reboot the system. I hope you find it working good


Does the CPU usage is 100% also in safe mode ?

If not , uninstall the drivers, and see if cpu usage is still 100 % even in normal mode..

Hi snatchman85,
I suggest that you defragment the computer,and also you should
uninstall all the unnecessary programs installed in the computer.Also
you should run the  msconfig comand so as to disable some programs
loading up when the machines boots up

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