fresh install using refurb disc - key invalid

[eurosteve]

Long story -
laptop bought 2nd hand with win 7 home premium (later found out it was some dodgy upgrade or maybe illegal copy)
Just bought a disc on ebay with COA sticker sealed in the envelope , it is marked as not for commercial resale but intended for refurbished pc use - which is what i am trying to do.
However the activation is rejected due to the key being invalid.
Supposedly i can return it but this supplier has 99 % positive feedback so they must work ...
Is there some trick to to the install that i have missed maybe ?
so far all i did was pop the disc in and run it after backing up to external drive.

 

[eurosteve]

embarresing

Put my specs on and realised the 3 was a B

so all ok now !

 

[derekimo]

Yeah, the B always looks like an 8 to me, glad you got it solved.