Interesting. I picked up that 2009 Anti-Virus malware last weekend.
I was doing a search for a driver and clicked on a link thrown up
by Windows 'Live Search.' I got a pop-up, similar to an AVG anti virus
screen, and it started to pretend to search my computer and tell me
that I had 59 virus/malware/trojan etc.. on my computer.
I pulled the internet connection from the cable modem as soon as
I saw it, but it continued doing the pretend search and exhorting me
to download it's anti-virus program.
My genuine AVG program belatedly picked it up and popped it into
quarantine. I emptied the quarantine and deleted all temporary
internet files, where it had loaded itself.
I've not had any more problems, so far, but reading the informed
replies on this thread, it would seem that there is a possibility that
it may have 'transmogrified'

itself and be sitting somewhere else,
waiting to have another pop at me.
Would it be worth formatting drive C and reinstalling? I've done this
several times on computers before, so it doesn't hold any qualms
for me. I have the genuine discs/ drivers/ product keys/ program
discs/ recovery discs etc..