/diy/ - Do It Yourself

hi /diy/
First time browser here, I searched all 15 pages and didnt find what I was looking for so I'll just ask.
(I am also asking /g/ and /adv/)
I got hacked.
my computer is now restored back to factory settings.
my OS is windows xp
my antivirus protection is norton internet security 2005 and mcafee 2005.

tl;dr: My computer is restored to factory settings, what is the best antivirus protection/upgrades (free) for windows xp?

also random picture.