Pollywogs!

Once a month you'll defrag it, run an online spyware scanner and an online antivirus scanner.  It never hurts to have a second line of defense.

http://www.trendmicro.com/spyware-scan/ – spyware scanner

http://www.bitdefender.com/scan8/ie.html  – antivirus/antitrojan scanner

You'll need to use IE at the BitDefender site.