No you cannot be able to you will have to buy a new product key.
Can Windows Vista be installed on two computers with the same product key? On the computer I'm using right now I installed Vista to upgrade from XP but I have a computer that stopped working right like 5 years ago and I was hoping I could use the same product key to install Vista on this old computer hopefully so it would start working correctly and I could pawn it. I really doubt it but I thought I would ask before I try to do it.

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