Empty Temporary Internet Files:
Start>Run then type %temp%
Hit OK. Delete all files in that folder

Run Ad-aware SE and Spybot S&D scanners:

Ad-aware SE - http://www.majorgeeks.com/download506.html
Spybot-Search & Destroy - http://www.safer-networking.org/index.php?page=mirrors

Update the programs prior running a scan.
Reboot after using the programs.

Next, go to Housecall http://housecall.antivirus.com/housecall/start_corp.asp

If Ad-aware found anything but can't delete. Run an Ad-aware SE scan in Safe mode.