another thing, DONT download 'free AV or scannner' if its in pop-up box, thats' a definite warning sign, it IS a bad shit...dont touch it, close it, and if you can't shut up the computer - FAST.
even at that, it might be too late ...theres 50/50 chance it IS a malware...so try go for the fully loaded (and most expensive AV $30 even $50 a year is worth alot more than all your hard work, home, and finanical security are worth...put differently if you DID not have the best AV and DID nOT keep it updated you run the risk of picking up a malware, nagware, bribeware, and what have you...running up mich higher...