[MovedGoalPosts]

I'd be inclinded to suspect the installation CD that you used, didn't complete fully or in fact corrupted something. Modern windows (XP, Vista) includes all the networking stuff you need for the connection, once you have run all the manufacturer's driver install routines for any inbuilt wireless and network cards for your computer.

If your computer is connecting wired to your modem, then it should also be able to connect wired to your router. Get a wired conection sorted first and worry about wireless later. You can't set the wireless connection options on the router untill wired is running and then you can log into the router via your internet explorer to check the SSID (network name) WAP (security settings) and the like.

Check your network connection (TCP/IP) properties are all set to auto on the computer. Equally your internet explorer should be set to auto detect, with dial a connection unchecked. Power off all the modem, router, computer. Make your new wired connections between all three, power modem and let settle, then router and let settle then computer.