[Ham-Computers] Network/Virus problem?

[WØQFC]

I have a situation that I do not have a answer for:

My 'home network', running six computers. Works ok but I keep getting a 
virus that I think is coming from the son's computer. All of the computers 
are running XP PRO except his ~ Windows ME.

I have Windows OneCare installed on my machines, which has  virus and 
firewall programs.

I have high-speed cable and use a Belkin router.

The question is How can I isolate the son's computer from the network so 
that anything he might get on his machine does not allow anything to infect 
mine?

TIA

73

Gene, WØQFC

www.w0qfc.com