MS's AV beats free AVG without sweat. Try it (if your windows is legit
)
Spybot is free so I'd highly recommend it too.
Autoruns/Hijackthis both great products, but be very
VERY VERYcareful with both as you can do a lot of damage with them.
I also found that Windows System Restore rollback, if not damaged by virus, works quite well in most cases...