I agree it sounds like a malicious code doing a number on your system, try this link: http://www.sysinternals.com/Utilitie...***plorer.html
and download the program, the link is near the bottom of the page.
It allows you to see each process (including ones task manager doesn't see) in a tree format so you can start in a lower branch and work your way up to larger programs. (eg: svchost.exe would be listed as a branch of services.exe )
-hope this sheds some light on the issue