If your friend has an older & slower system but has broadband, I'd have him hookup a router for the hardware firewall alone. Then use the free online scanners like housecall along with a simple, basic & free software firewall like ZoneAlarm.

Years ago software & hardware firewalls were looked as only needed or used by the tech heads, but it's really a must for anyone hooked up to the internet.

I've found too many antivirus program that might detect a virus but is then unable to fix or delete it. A good firewall is your first and most important defence!