If you click on Start, connect to and then select show all connections does your network show up? If not then I suspect your Windows Zero configuration service is not started. Goto control panel, admin, services and be sure it's started.

Are you using any type of security on the router like WPA or WEP? Look at the network settings of one that is working and be sure you are set the same on the one that does not work.

Also, if your router is using MAC filtering be sure your PC's MAC address is added to the routers list of acceptable MACs.

Try these and let me know what you find.