I have a valid RTM Win XP installation cd and license and wanted to slipstream SP3 into it. Using my other computer that runs Vista, I tried all of the following to no avail. In all cases, I would get the "Product ID is not valid" message and the installation wouldn't continue: slipstream SP3 using 1.4.5 slipstream SP2 and then SP3 using 1.4.5 slipstream SP3 using 1.4.1 Ultimately, I slipstreamed SP2 and will just use Windows Update to get to SP3. Do you think there is something I did wrong? Does 1.4.5 on Vista definitely work for SP3?