We have key checkers and they return lots of info. One thing I noticed is that when checking keys (sample output) Product Key: CENSORED Validity: Valid Product ID: 82503-566-0042044-48650 Advanced PID: 82503-00096-566-004204-03-1033-7601.0000-0292011 Activation ID: fdf3ecb9-b56f-43b2-a9b8-1b48b6bae1a7 Product Description: RTM_ProPlus_MAK Edition Type: ProPlusVL Edition ID: X16-08116 Key Type: Volume:MAK Eula: ltMAK is that the Product ID: part can vary, but the Advanced PID Part is ALWAYS the same. There is also convenient WMI function in OSPPSVC that returns Advanced PID's for all your installed keys. I need to be able to tell what keys are installed (All 25 digits not 5) to be able to implement a new backup/restore system that could work after a reformat as it involves reinstalling the keys. There has to be some kind of process to convert this to a 25 digit key given its uniqueness and doing so would be of great use.