Try other sources and scan, like Spybot S&D, MalwareBytes, and Superantispyware. But it sounds like you have malware on your PC. I had something similar problem with McCrappy (McAfee) that allowed a download, found a problem, but by then it was too late and the infection occured and McCrappy found nothing, and only these others could help identify and cure the problem.

Thanks for the advice metalman640. I installed SuperAntiSpyware and run a full scan, problem solved.