CPU usage at 100% but allocated among processes

[m1150]

I'm having a weird problem with Windows 2000 Version 5.0 that has stumped our IT guy.

About once a day, the computer starts to go very slowly. When I open up the task manager, I see CPU usage is stuck at 100%, with System Idle Process at 0%.

But there's no one process taking up all the CPU usage. Instead, the 100% is allocated among the programs that are open -- Outlook, Firefox, the virus scanner and even the Task Manager itself. The listed CPU usage bears no relation to how much CPU usage the processes should require. For example, it might say 50% CPU usage for Outlook (even though I'm not getting or sending any e-mail or doing anything in Outlook) and 50% for the task manager. Then it might shift to 33% Outlook, 33% task manager and 33% Mcshield.

The CPU usage will stay at 100% for several minutes, then return to normal. In recent days, the problem has been lasting longer. It used to happen for only a couple of minutes, but now it's taking 10 minutes or so to go back to normal.

This shouldn't be a memory problem, since I seem to have enough memory for the programs I run (usually just Firefox, word processor, Outlook, Adobe Acrobat Reader and sometimes Excel).

System specs:

Windows 2000 Version 5.0 (Build 2195: Service Pack 4)
Computer: Dell OptiPlex GX110 -- x86 Family 6 Model 8 Stepping 6 AT/AT Compatible, 522,476 KB RAM
33.2 GB hard drive

Thanks for your help.

[patio]

Depending on which window you are looking at in task manager it is supposed to add up to 100%.
DLoad and install Process Explorer which will give you and the IT guy more detailed info.

[m1150]

Depending on which window you are looking at in task manager it is supposed to add up to 100%.
DLoad and install Process Explorer which will give you and the IT guy more detailed info.

Yeah, but isn't System Idle Process supposed to take up the bulk of the CPU usage when nothing is happening?

Thanks for the Process Explorer idea.

[2k_dummy]

Have you checked the indexing service? It is a resource hog and should be disabled if it isn't already.

[SuperDave]

M1150, Here's what I found that might explain what's happening with your computer.
http://www.computerhope.com/issues/ch000616.htm