Recently New XP Dell Optiplex 745 becomes unresponsive

[Guest]

I purchased a Dell Optiplex 745 a couple of months ago for someone here at
our offices. For the last several weeks, this machine has become almost
unusable. The person that uses it is one of the more knowledgeable users we
have, she is very cautious and doesn't download crap off the net.

When she first turns it on, it runs great, but in the course of just an hour
or two, the think becomes so slow, I can't see how she uses it. Right-click
on an icon on the desktop and it will take over 30 seconds for the menu to
pop up.

She has current anti-virus software installed and no extra software/apps
that aren't required. When it grinds to a halt, task manager doesn't really
identify the problem, like one process hogging all of the cpu.

What can I do to locate the cause of this problem. If I could at least
identify a pattern or something to give me SOME idea of a general area to
look in, but there is nothing telling so far. If I can at least determine
what is causing the problem, then I could fix it.

There is another machine in the office, same model, purchased at the same
time, it runs fine.

Any suggestions besides fdisk and start from scratch?

 

[Guest]

Right-click is slow or weird behavior caused by context menu handlers:
http://windowsxp.mvps.org/slowrightclick.htm