I'm surprised no one has suggested this yet. Run a scan with some of the spyware scanners and check for spyware. Adaware, Spybot Search and Destroy, Spyware Blaster, etc. A really good one I've found was PestPatrol. It found 800 or so items on a community work computer after all the others were run. Also, it would probably be a good idea to run a defrag. Funny thing with my brand spankin new computer, when I turned it on for the first time and set it up, the hard drive was 19% fragmented before I touched anything other than the initial setup stuff.