Sometimes the anti-virus you are using lets things slide by such as trojans and adware. When that happens, it is always good to try an on-line scan to see if anything has been bypassed.
The reason I mention Avast Free quite often is because I found it to be the ABSOLUTE best real-time AV on the internet. I have used Norton, McAfee, AVG and now Avast and have never looked back. For Home use it is AWESOME, NO MUSS NO FUSS maintenance free AV
Housecall- A good online AV scan that allows you to remove whatever it finds.
Bit Defender- Another good on-line fully functional scan.
Kaspersky- yet another fully functional scanner
Dr Web Cure-it- one more for you to try, just D/L this program to your desktop and run it.