It's Pro, the original, not SP1... And I tried using ProductID just in case... I might even go away and try ProductID="XXXXX-XXXXX-XXXXX-XXXXX-XXXXX" just in case that works. In the meantime I'm running out of ideas... it's definately the right key in the answer file, and the key definately works... And since this is now the only bit that needs me to be there I'd like to know why... Please, please, please, please, please let someone know have the answer...