It sounds like your antivirus has been completely screwed over by a virus.
If it's gotten to that point, good luck, even if you get rid of it who knows what kind of damage it has already done.
Edit: in my case I have my system files backed and would be able to restore them without reformatting my drive and losing all my games and whatnot (i would then reinstall the antivirus and go about getting rid of the problem). but since you are asking about this, here, of all places I'm betting you didn't do that.