Under attack

I confess. I clicked when I shouldn't have clicked...
My home computer is being attacked by spyware, it's making surfing difficult. Been running Adaware and AVG constantly the last 2 days but it just won't heal...just to give you an idea of the scale of the attack, Adaware came up with 800 critical objects last night.
Anyone recommend a top anti-spyware (not anti-virus), preferably a freebie?