I can't connect on the internet when my PC is connected to my Linksys router?

I can't connect on the internet when my PC is connected to my Linksys router. When I connect my modem directly to my PC, the internet works fine. But when I connect the modem to my Linksys router and then connect the router to my PC, I can't use the internet. My router was working fine until this happened. What can I do to solve this? My router is Linksys WRT54G ver. 7.|||there is a reset button on the router try it other than that I dunno.|||It sounds like your router is dead.