How was your previous network set up before the death of the router?
Was the router doing DHCP, or did you have static IP Addresses?
Your Linksys router should have a DEFAULT IP ADDRESS of 192.168.1.1. On each computer, go to START > RUN, then type 'CMD' and press enter. You should now have a command prompt open. Next step is to type IPCONFIG with the computer plugged into the router. If your computer is 192.168.1.X, try performing a 'PING 192.168.1.1' to see if you can ping the router.
If your PC's come up as 169.X.X.X, then you are not getting IP addresses from the Linksys router. If you want to reset the router to factory default, there should be a small button on the back of the router. That button will be labeled 'RESET' and you will need a sharp pencil, paper clip, or safety pin to press it.