re-start under safe mode (press f-8 when computer boots and select safe mode) .
click start
click on the RUN icon
type msconfig
select the startup tab
then UN-CHECK the programs you DO NOT want to load when windows starts. (Be careful not to un-check something important)
sometimes you have too many programs running at startup, not giving your operating system a chance to do anything.
Also do a virus check and SPYWARE check while you're in SAFEMODE. I'm betting you're gonna have a few of each.