Okay, I think I see what happened. On the linked page, to the left, there's a link to "get Free AVG," and that's the road you want to take. They have much bigger, prettier buttons for the "AVG Full." Ignore them. They are the Devil's work.

Oh, my poor, beloved XP box. Repository of my games and my, uh, educational videos. I will be very sad if I can't recusitate you, little homemade piece of junk ...