windows and anti virus question

I'm going to format my computer. but if I do, then I have to install the normal windows with no sp2 pack again. Which means I will have less virus protection. What do you think I should do(I can't update because...erm you know)? and could you recommand me some good anti virus program?

GET BELARC ADVISOR (CHECK GOOGLE)
INSTALL IT
RUN IT
IT WILL TELL YOU WHAT UPDATES YOU NEED
CLICK ON THEM
FOR EACH OF THEM, YOU WILL BE TRANSFERRED TO MICROSOFT SITE
SITE WILL ASK IF YOU ARE CONSUMER OR IT PRO, SAY IT PRO
DOWNLOAD UPDATE
RUN UPDATE
REPEAT 80 TIMES
NO WGA NEEDED
?????
PROFIT