Linksys WRT54GC v2.0 - all connection lights flashing

"Sounds like you may have a bricked router. You could try again to hold the reset for longer than 30 seconds, and make sure your computer that you have attached via Ethernet to port 1 of the linksys is set to automatically obtain IP via DHCP.

If the multiple 30 - 60 second resets are not working to bring it back, there is an option of flashing but without some sort of connection to it I doubt that would work either."

I had the same problem for about an hour late one night. I decided to go to bed and resume working on it the next morning. Everything was working perfectly the next morning. Waiting is undoubtedly not a general solution, but it worked once.