Invalid windows 7 key

Brianl74

Reputable
May 5, 2014
33
0
4,530
So i recently got a windows 7 pro sp1 64bit disk off ebay. It just came in a little pack with a product key. After installing onto my brand new desktop it asked me to validate the copy so i enter the code and i got this error 0xc004c008. On top of the disk it says "Already installed on your computer" so i'm assuming it's just a reinstall disk but windows 7 still went on fine but it's just not validating. Any help would be great