My office computer has become very sluggish, to the point that sometimes (not always) clicking on keyboard arrows while browsing a table it has a noticeable pause between fields. This has me scared that it may have a keylogger living inside. I have up-to-date virus software.

A coworker had a similar problem and reformated and started reinstalling software with much increased speed, which really hints to either malware or conflicts of some sort. Any suggestions short of the same drastic approach?

TIA,

Alex