Perform the following:
Disable System Restore
Perform an online virus scan. Antivirus on line checks:-
Panda click here
Trend Online Check click here
Download, update, and run these tools:
Spybot S&D click here
Adaware click here
CW Shredder click here
Repeat as necessary until clean.
To protect against reinfection, download and use these:
Spywareblaster click here
Malware-blocking HOSTS file click here
Optionally Reenable System Restore
If you still experience problems after doing these steps, download HijackThis click here post a log to this forum.