Had to restore and now windows wont activate

I have a Dell All in one with windows 8 factory installed. I could not boot to windows yesterday and doing restore to previous dates did not resolve the problem. I was able to run the dell back up and recovery app which did a current back up and then reloaded windows and the computer to factory conditions and then installed my personal files back onto it. Now I get a message saying windows cannot be activated and I am not sure what to do.

I get Error Code: 0x8004F80B

Error description: Unable to find a detailed error description.

Unknown facility code of :0x04 (04L)

Facility error: 0xF80B (63499L)