said by dave:I assume the key provided with the PC would work for Windows 7 from the same vendor - but since I've only does this with volume-licensed versions, I can't say for certain.
That has not been MY experience with keys from M$.
Using XP Pro as an example :
I personally have demonstrated that XPP VL keys are not accepted by an XPP OEM install, and vice versa (and the vice versa matters more, if you are only trying to make legit an illegally installed VL OS with an OEM key which is not currently in use elsewhere), and if they are not accepted WITHIN different flavours of a product version, then I quite doubt that they would be accepted in another version.