slow running computer help

  Hey People:

My PC is running win xp and is running really slow.  Seems like the computer
is running something in the background.  Getting this running sound like a
processor is running in the background.  This is really causing me problems
running a browser and my microsoft money hangs when I click on a monthly
report that I was viewing when I received an update.

Any diagnostic suggestions?  Tried to reinstall ms money, my virus software
(mcafee) or reset the computer to an earlier date without success.

Thanks much.  

 Without specific information, we're guessing.  I'm not MS; just a friendly
adviser.
Do you have memory enough to run the applications you do run?
What programs run as you start up the computer?

With XP and minimal other applications, 512 MB should be OK, but I'd still
advise 1 GB.
The biggest suggestion would be to clean out the startup folder, and stop
other programs from using the memory you do have.