virus after windows 2000 install

ive been connected to the net like a hour i got 3 virusis already 2were the same and one was W32.HLLW.Nebiwo the other i forgot how do i keep from getting them goodthing for my antivirus that gets them i have all the updates

Turn on a software firewall then get all the MS updates.

i have all the updates and i dont have a firewall i never needone in xp i always had it down