I would try these for starters: Ad-Aware and Spybot to
search for spyware and Trendmicro for a online virus
scan, they are all free.
Look for Ad-Aware SE Personal:
http://www.lavasoftusa.com/default.shtml.en
Spybot:
http://www.safer-networking.org/en/download/index.html
Online Virus scanner:
http://housecall.trendmicro.com/housecall/start_corp.asp
If your able, run the virus scan first.
It would be best to run the spyware scanners in safe
mode, but make sure to update them before re-starting in
safe mode. Hit F8 a few times until a menu comes up when
your computer restarts, pick safe mode. Run the programs
after windows starts up. In fact, I'd run them twice in
safe mode, but reboot in between.
I hope that helps you. I would have said it was a video
problem, but you said its 'JUST' the start menu area?