Windows 8 Product Key left my BIOS

Hi all,

I have a Alienware X51.

Recently, i have issued some problems which eventually led me to restore the fabric image by using Alien Respawn.

After restoring the pc, I installed windows' updates normally.

I'm not sure wether the problem came after the restoration or the updates, but now my windows 8 isn't activated anymore, as:

• In the low-left corner of the screen it is written "Windows 8 Build 9200"
• If i follow "control panel -> system -> Windows Activation", it says "Serial Number: Not available"
• Sometimes, it randomly appears a menu which says "go to settings to activate your windows". If I click the button to do it, nothing happens.

I read that in Dell PCs the Windows activation number is imprinted in the BIOS, but it seems that something went wrong with the restoration: what to do?

Thank you