Mary-Jo Foley posted a news story that the Windows 7 upgrade offer for Windows Vista PCs is only valid for the first 25 machines.

Via the program, users who purchase new PCs with Windows Vista preloaded from participating PC makers and retailers, as of June 26, will get coupons entitling them to a free copy of Windows 7 some time on or after October 22. The fine print: As InformationWeek noted, the Upgrade Option program maxes out at 25 upgrade coupons per customer.

>> Windows 7 Upgrade deal maxes out at 25 PCs