Grab the PID checker from here,
and run it, hit the Windows key, that will fill in the key used to install Windows, use that key and go to the online PID checker here.
I believe Ultimate PID Checker has only one black listed key - a Lenovo SLP Key for Windows 7, that's why I would use the online checker to see if there is a problem with your key.
Once you know what the key is and what version of Windows it's for grab the correct ISO from a Microsoft source and check the hash and try to install with your key. You did burn the recovery discs, right?
Be careful about where you get your ISO from, CHECK YOUR HASHES -> if you Google -> Windows 8 hashes -> you will be pointed here.
- and by here, I mean Neowin, the link is a thread on Neowin.
There is no guarantee this will work, so keep your restore disc handy. Good Luck.