does networking your home pc make it more vulnerable

[-gem-]

to internet attacks? If you have a wireless router and you now run a network off it and add other computers in XP, is it now more susceptible to attack from trojans hackers and the like?

[pug100]

Not more open to internet attacks but beware of war drivers or people piggybacking your internet service via the wireless connection. If you do not need the wireless bit it can be disabled within the admin pages or severely restricted by removing the aerial (most screw into the back of the router and are easily removed).
If you use wpa encryption rather than wep that will also help, change the broadcast ident (SSID) to something other than the deault ( instead of Netgear label it as a random letters or number, 453 or jkl) or switch it off altogether. Switch off the router / modem when not in use then nobody can get in.

More info here

http://compnetworking.about.com/od/wirelesssec urity/tp/wifisecurity.htm