anjlbeing

can windows antivirus 7 automatically scan and detect viruses in my computer even if i haven't downloaded it? I was in the middle of browsing a usual site, and it won't stop popping up warnings. And when I go to the fix button, it wants me to put in card info and pay 80 bucks. I have mcafee, wouldn't this catch these supposed 22 viruses?
How do I get it out of my computer? I downloaded it, but can't seem to remove it. Don't worry. I didn't put any info in.