[Hamuko]

Microsoft wants the $25 if you resell a computer without a Certificate of Authenticity and the recovery media (if it came with one). If you don't have both, then according to Microsoft, the computer is unlicensed, as the Certificate of Authenticity is not the same as a license.

Of course, it would be easy to pass off refurbished machines as having valid licenses if you had the Certificate of Authenticity and a disc that looks like a genuine Dell recovery disc for Windows Whatever with holograms and all that jazz.