Could be some malware. Malicious software that are installed together with cracked games, some newbie installing browser from site that can't be trusted, that gets in some tool bars, even that "Driver Booster 3" could've came with some malicious software. It should show up in the Programs and Features.. If basically nothing worked, that most likely it's some virus, as someone already stated. You could try to show us every program that is installed so we can determine what should be deleted and what could be malicious software. If nothing like that works, then the only solution I can think of is re-installing PC.