do- spybot-search and destroy; adaware; micorsoft antispyware
then reboot, and do them again, (make sure they are ALL the new updated versions, sometimes you can download old versions and they make you update it after you install it)
then get spywareblaster, and spywareguard, which protect against viruses, and reboot.
then run updated version of antivirus software. that should clear it up, and if not another option is to get hijackthis, which shows you all your registry files and running processes, and you can post it up and find out if anything is wrong in there.