You can try this as a little trick.
1: Re-set router then power it down
2: Unplug Cat-5 cable and plug into opposite ends, but plug it into a different port. (Ex. if it is in 1, try 4)
3: turn everything back on then type the Linksys IP in Internet Explorer -- 192.168.1.1 User: admin Pass: admin (after reset)
4: set-up router (PPPOE or if provider use's other)
Number 3 sounds really stupid, but trust me, it has worked on more than one occasion in the 2 years of working for a ISP as tech support.