Winfixer

Suddenly I started getting these popups whenever I turn on my computer.I use adware,spysubtract the new microsoft antispyware beta, norton antivirus,and win patrol. None of them detect this one. Winfixer always tries to tell me my computer is at risk and tries to sell me their software and all sorts of traffic,shopping type popups.
Xoft Spy supposedly gets rid of this one but I can't find any reputable sources to verify this. I'll spend the money for the software if I know it works.

Please Help!!!!!