Microsoft may disable upgraded PCs
If the product ID number is already registered against a different PC, the clearing house will not authorise the activation of the software. "We will know whether you have activated that particular copy of Windows before," said Laver. "If this is the second time then we'll reactivate it immediately, but if this is the 30th time you have phoned up to reactivate then it is obvious you are pirating and we will not reactivate it."
The link for this article located at ZDNet UK is no longer available.