I can vouch for Malwarebytes. I have used it and it does a good job of finding viruses and cleaning your computer. Also in the near future you may want to get some virus protection software. The university I am currently at offers us free Symantec virus protection software and it is pretty good. I switched to Microsoft Security Essentials half way through last year though, and I like it a little more. Microsoft Security Essentials is free. You can read about it and download it here->http://www.microsoft.com/security_essentials/. I hope this is helpful.