Please post this in your WIN OPERATEING SYSTEMS forum. I would appreciate a definitive answer. I have 2 DELL XP reinstalltion CDs, PRO and HOME,GREEN and BLUE. The only restictions that I can see is that it is designed to reinstall the os that was factory installed. In my experience that is not entirely true. I used it to fix 3 DIMENSIONS 8100s which needed new(harvested) hdds. These hard drives all came from non dells, The 3 OSs were NOT xp. They were win 98, 2000, ME. During the install process the CD formats(wipes clean) the existing OS. The drive is now no different than a new one in the box. The next step is the OS installation. In the end a working machine is presented in RAW condition, that is only the OSs built in programs software are present, IE, OE, scan wizard, ect. All the internal hardware was detected and drivers installed. 100% functional as is. Only the final touches are needed. Having this explanation in mind, would it not be possible to use either of these CDs to do the same job on a non dell? I would imagine that only the preparation process would be different, as in getting into the bios and boot screens, putting the cd drive as the first device, and saving those choices to get to the OS set up screen. One of these has a product key, the other does not. The key was NOT asked for, and activation was NOT asked for. My logic says that this process should work on any tower since it wipes the hdd clean without regard to the existing OS installed on THAT drive. Two friends tried it as an experiment, one on a GATEWAY and one on an HP. One was win 2000 and one was XP MEDIA CENTER. Both were 100% successful. No issues at all. The cd did not seem to care that it was reanimating a tower it did not come with. Please tell me if my logic is correct. If yes than I will be able to get more towers to work for that reason, I am willing to reload the OS only to find out later that the tower has other issues. I only lose the time it takes to do it. Being retired I have lots of that. You might want to try this yourself to verify that what I think should happen will indeed happen.