Ok first you want to download Malwarebytes Anti Malware. from http://www.malwarebytes.org/ and then you want to run a scan with that. For an anti-virus after that's done, DO NOT i repeat, DO NOT get Norton OR Mcafee. They are the worst anti-virus softwares. Get Kaspersky 2011 or ESET smart security 4 and run Malwarebytes everyday as a second opinion. If your computer is fast, get Kaspersky 2011. If it is slow(er) then get ESET smart security 4.