kapaopango writes "Ars Technica is reporting that upgrade versions of Windows Vista Home Basic, Premium, and Starter Edition cannot be installed on a PC unless Windows XP or Windows 2000 is already installed. This is a change from previous versions of Windows, which only required a valid license key. This change has the potential to make disaster recovery very tedious. The article says: 'For its part, Microsoft seems to be confident that the Vista repair process should be sufficient to solve any problems with the OS, since otherwise the only option for disaster recovery in the absence of backups would be to wipe a machine, install XP, and then upgrade to Vista. This will certainly make disaster recovery a more irritating experience.'"