If you can't even console into the router (what kind of router is this anyway) then you're screwed. Call the manufacturer, see if there's a way to reset it so that it like reads a hard coded stored copy of the original firmware and boots from that. Or, so that it will read boot information from a bootp server, and then read the firmware from a tftp server. However if it's a cheap home DSL/Cable router, you're probably screwed. Probably need to replace the chip if it's made like a motherboard BIOS or send it in for service.