By upgrade, I assume you mean a firmware upgrade. We may need more info. What process did you try? Power off the router and back on to see if that makes a difference. When it comes back on, what lights do you see? Can you sign on to the router's user interface? Is the network WAN IP address zeros or does it have some numbers? If zero, follow the instructions in the post of not obtaining IP address). Try a factory reset and which sets all the settings back to factory settings. Then reenter the settings as if it is a new router.