Computer Randomly Moves Slow

[TheOneWizard]

A while ago (I can't remember when) my computer started having a problem where sometimes I would boot up the system and everything would move slowly. However, sometimes I would turn it on and everything would be fine. I could never figure out the reason for it working sometimes and not others.

I've tried simple solutions like defragging the hard drive to no effect. The computer scans for viruses every day and nothing ever comes up in that. My friend suggested looking in the Task Manager to see if there is some process that is eating up an inordinate amount of CPU, but there was nothing that seemed out of the ordinary. The CPU does run at 100% under the performance tag whenever I do or even type anything.

Unfortuantely the problem seems to have gotten worse. Every time I start it up the computer has been running slowly. I considered taking it to Geek Squad but they charge $200 and it hardly seems worth it. My comps a little old (I got it in 2001) but it's been upgraded a few times.

Thanks for any suggestions of you have.