your friend's pc can be infected with a virus thru diskettes, flash disks and even cd copies w/c contain 'em so you gotta give him an anti-virus. i recomment Nod32. however, i do not know any offline updating with nod 32. what your going to do to upgrade its virus definitions is to bring your friend's cpu to your house and connect him thru your internet at least twice a month, its gonna keep his pc clean.
i understand that, but just have buddies who bring over the stuff virus scan it...
oh well. but if u need one, try doing the manual updates with avg..
and yeh nod32 is great