Computer not Recognizing Ethernet Connection

Out of the clear blue as I was connected to the internet via DSL using a Linksys wireless G router between the primary modem and the PC the “green light” on the router disappeared and my internet connection is gone. When i reboot the computer the green light comes on so it is recognizing the ethernet cable until the reboot is finished, then it disappears. The LAN connections disappeared so somehow something happened that blew away my connectivity. I’ve tried reloading drivers disk but nothing works. It appears ethernet connection/card has been wiped out. Has anyone ever seen anything like this happen before?