Computer slows to 1% speed randomly and at startup

Hi all:

System: Dell Dimension E510, Windows XP SP3, 2GB Ram, purchased new in
2005.

Several days ago, my computer started randomly slowing down. Task
Manager indicated the CPU was at 1% or below. During these slow
periods, something as simple as refreshing the desktop icons could
take 5 minutes or more. This now happens every time on startup,
lasting about 15-20 minutes. It also happens randomly during the
day. I have:

1: Run disk cleanup, disk deframenter, etc.

2: Updated all virus definitions for McAfee Security Center, scanned,
found nothing.

3: Downloaded and run the Microsoft Malicious Software Removal Tool.

4: Downloaded and run AdAware Anniversary Edition, which removed a few
cookies, but didn't find anything else.

5: Installed Active SMART, which is monitoring the HD, but has
reported all is good for the last several days.

6: Installed Eusing registry cleaner, and done one cleanup cycle with
no effect upon the problem.

I have just about convinced myself that it is not a software or HD
problem. I noticed that while the main cooling fan works, it never
switches to high speed. I wonder if the CPU is overheating and going
into some limp mode. I have opened the case, vacuumed out all the
dust, and verified visually that the fan operates at slow speed.
Since the fan works, I assume the issue is with some temperature
sensor that tells the fan to speed up. I have tried using Speedfan to
monitor CPU temp or manipulate the fan speed, but it didn't work. I
have found no built-in utility for checking this. I did try leaving
the case open and using an external fan, but the computer case design
makes it difficult to direct airflow into the CPU heatsink from
outside. Regardless, the problem persists.

I could probably hot-wire the cooling fan to stay at high speed all
the time, but it's very loud, so I would only do this as a temporary
measure. Where might I find the temperature sensor, or is it built
into the CPU? Is there a utility for monitoring this? I'v'e spend a
couple of hours on the Dell support site, but not found any answers.
Posts to their tech support forum go unanswered, as well.

Thanks in advance,
John.

Tried it in safe mode? (I'm thinking driver problem)
Have you tested your memory? (I'm thinking faulty memory module)
www.memtest86.org

I read a while back about a computer which was copying large files extremely
slowly. It turned out that the hard disk was not using the correct mode to
copy files. I'll look up the details if the above is not helping.

On Fri, 10 Apr 2009 17:10:33 +0100, 123Jim wrote:


Yeah, Windows XP has a sad habit of dropping back to PIO mode from time
to time, and without giving any warning to the user. Rebooting won't
reset it either, so you have to re-enable DMA mode manually.

I've had that happen to me at least twice.

Thanks I could not remember the name of the modes

Here's why it happens and how to change it:
http://www.microsoft.com/whdc/device/storage/IDE-DMA.mspx

device/storage/IDE-DMA.mspx

123Jim:

I investigated this, but everything is set to use DMA.

Regards,
John.