That Netgear WGR614 router has a feature called ¨Default DMZ server¨.
DMZ is a special logical zone located between the Internet and your Intranet, I mean your home network.
Theory says that DMZ computers can access the Internet but cannot access the Intranet: Intranet computers can access the Internet and also they can interact with DMZ-located computers (the firewall allow communications DMZ->Intranet when they are answers to questions issued from the Intranet, otherwise traffic originated at DMZ with destination the Intranet is blocked).
So, if you define a default DMZ server address that is located inside your home network address space but
- is not already assigned to any existing, "good" computer
- is not included in the DHCP address space
then you can assign that IP address to any virus infected or unreliable computer you are working on, in the knowledge that it will not interact with the rest of the computers at home.
This is easy to do (page 6-8 of the config manual for the router) and you need special HW.
It will give you the chance to have just ONE unreliable computer online, in case you need more than one unreliable computer online, next to the rest of your hardware..... think twice!
Hope this helps, regards.