Super computer slowed under vista ultimate

Hello all,
I am under vista ultimate,my super computer is idle

proc-> Intel Core 2quad Q6600 2.4GHz
ram-> 2 gb
feat-> visa edition sp1 32bits

It is about a week when, I had a malware scan with byte's, a scan with avast and a scan with spyware terminator. I cleaned with CCleaner and tune up utilities 2008.
But nothing is working out.
please help.

You just try to restore your system to the previous date, and remove all the junk from the main drive from where system boot, such as C drive.