Computer Won't Recognize Connection?

The main computer received a virus and I had to reinstall the operating system. When I did, however, all settings disappeared. The lights on the modem and router are fine, and the secondary computer has full access to the Internet. I also can use my Wii with the Internet. I tried setting up the router again but the main computer won't load the web-based configuration utility page. The secondary computer, however, can. I tried plugging the modem directly into the computer but the computer didn't seem to recognize it either. I bought a new router, thinking if I got software it would automatically set everything. However, the router I received came with zero software. I plugged it in and the computer still couldn't connect to the config page. I am at a loss as what else to do here.

My old router is a Motorola WR850G and my new one is a Netgear WR614 v9. Either would be fine to use, as long as I can get both computers to connect. The host computer has XP and the secondary Vista.