The only shortcoming I see here, and yes most of these products work well for retrieving lost ID tags for the software (OS), on a running computer. If you have lost the “product code key” for setting up the PC, that is a whole diffeerent ball game. I think you can get a new product ID code by calling Microsoft directly, or if it is like a “proprietary disk” like for an emachine or HP, IBM, or any of those things, you MIGHT be able to get a new ID code from them MAYBE. It might be cheaper and easier to just “bite the bullet” and go and buy a new installation disk.