Clear all your temp files.
Download Malwarebytes Anti-Malware -> install -> update -> run. also run it from safe mode.
download CWShredder and run it. then download Spybot S&D -> update it and run it - also run it from safe mode.
if this doesnt help download Hijackthis and run it and look for suspicious entries. Dont delete things you are unsure of, if you are unsure, save logfile and come back and post it for people to have a look.