I recommend what Aragorn said, also run Adaware on the Full Scan instead of fast scan, it may find something, also I would download and run
CCleaner
Use that to flush your cache's out and clean your registry, then pop into tools and check whats booting on your start up.
Alternatively goto start/run/ and type in msconfig and disable any "strange" startup items. If your not sure post here and I'm sure we can nail it down
