Blame explorer.exe?

Although CPU does not show a steady increased level but only spikes (I suspect the frequency may be such not all get registered), fans are audibly working overtime for no obvious reason even though CPU may stand at 2%. As application, only Firefox is on. System idle mostly at 98%, excepting taskmgr.exe (2%) only explorer.exe seems active continuously; it is listed under User, not System, and it is the only instance of explorer.exe visible. On average I have 38 processes running all in all. Having done search, I have multiple locations for it: C:\WINDOWS C:\WINDOWS\$NtServicePackUninstall$ C;\WINDOWS\$NtUninstallKB820291$ C;\WINDOWS\$NtUninstallKB938828$ C:\WINDOWS\ServicePackFiles\i386 C:\WINDOWS\$hf_mig$\KB938828\SP2QFE Have already deleted explorer.exe from Prefetch; AVG 7.5 finds nothing, neither does a-squared. Makes me wonder what the culprit may be? Running XP SP2 home, with Outpost firewall, and have just removed explorer.exe from the list of anti-leak exlusions just in case. In the past, there were requests to grant it web access which I blocked. It is all very strange. Any suggestions, anyone?

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38 running processes is a little high but not excessive. I typically have 33.

You could also try turning of indexing. It runs under the auspices of explorer.exe. It's only affect is a slightly slower response time when searching your hard drive for data.

To turn off indexing on a per drive basis:

1. Open up "My Computer."
2. Right-click on your hard drive (C:, D:, etc.) and choose "Properties."
3. Uncheck the box at the bottom that reads "Allow Indexing Service to…"
4. Click OK, and files will be removed from indexing memory. This removal may take a few minutes to complete.

I think there is some confusion here, so here is my 2 cents:

38 processes is not too high. I have 41 and I know my system is clean, and running fine. 38 only suggests you have a few more things loading at boot time than Rich has (and a few less than me). As long as you know what each item is, and you have enough RAM to support everything, you are fine with 38, or more.

How much RAM do you have? How much free disk space do you have?

Also, understand that "explorer.exe" is the Windows shell. It is NOT Internet Explorer, whose file name is iexplorer.exe. Generally, explorer.exe needs access to everything, and in Task Manager, it should be listed under your user name.

When are these spikes occurring? When the system is otherwise idle? Or right in the middle of you doing things?

The below are all enhanced Task Manager type programs that will show you what is running. Each is nice in its own way. What's Running is probably the easiest, with AutoRuns for the more experienced, and Process Explorer the most popular. With these, for example, you can see what processes are using the various svchost.exe images.

AutoRuns for Windows
Process Explorer
What's Running

Also, I am confused as to why you deleted explorer from the prefetch. Folks generally NEVER should touch the prefetch. When you clear the prefetch, XP must (and will start immedially) relearning how you use your system. This means boot times and your favorite load times will be longer, until XP learns your usage patterns and re-populates the prefetch folder again. The prefetch folder is self-regulating, and it can NEVER get too big as it has a 128 file limit.

Thank you both for suggestions and advice. In the meantime I have cleansed the system of dead wood, and the issue is no longer. RAM is at 512 MB, which I believe is at the bottom what I should have taking into account how I run the laptop. I am thinking about doubling it anyway, esp. since the not-too-big HD is more than half-full (21 out of 37 GB). I take on board the point about prefetch; the spiking problem was concurrent to my having changed location. I had trouble connecting to the local wi-fi, possibly due to my using Outpost firewall (a driver issue?? - repeated Microsoft warning). It sorted itself out within 24 hours, and my gear is now running perfectly. I have also considered opening the laptop and blowing away any accumulated dust just in case it was part of the increased ventilation due to overheating, with no particular application to blame. The laptop may have been in several different positions during transport, with dust possibly shifting to sensitive spots. So thanks again!

RAM is at 512 MB, which I believe is at the bottom what I should have taking into account how I run the laptop. I am thinking about doubling it anyway, esp. since the not-too-big HD is more than half-full (21 out of 37 GB).

The two (RAM and HD) are not related in the way you are suggesting. That is, the size of the drive has little to do with it, as long as you have enough free space left for the Page File, and you have plenty.

However, if you add another 512Mb, you will see significant performance - in nearly all aspects of your computing. And that being a laptop, that means it uses on-board graphics - which means a significant chunk of that 512Mb is being taken for dedicated graphics processing. More RAM will also give your CPU and Windows a much bigger, and significantly faster, area to temporarily stash data - instead of thrashing the hard drive's Page File all the time.

Thank you for further elucidation, Digerati; boosting RAM is No. 1 on my to-do list.

These popular RAM makers have auto-scanning and/or manual entry RAM wizards to help you determine compatible RAM. For manual entry, enter/select the PC or motherboard make and model number and the wizard will list compatible RAM.

Crucial - Memory Advisor
Corsair - Memory Configurator (manual data entry only)
GeIL - Memory Configurator (manual data entry only)
Kingston - Memory Search (manual data entry only)
Mushkin - Advisor
OCZ - Memory Configurator (manual data entry only)
Patriot - Memory Search (manual data entry only)
PNY - Memory Configurator (manual data entry only)
SuperTalent - Memory Finder (manual data entry only)

The following retailers have auto-scanners and manual wizards. They sell brand name and/or "house" brand (re-branded) RAM.

Newegg - Memory Configurator System Tool
MemoryStock - Upgrade Configurator
18004Memory? - Configurator

I have already tried out Crucial; thanks for all the suggestions. I am sure I'll make good use of them. Having returned to base, I've done the dust removal on my laptop, too, but it was not as bad as I feared.