Microsoft Product Key Changer - 'corp' to OEM/Retail
Came across this last night and thought it might be handy to anyone else who fixes friends/staff PCs after work etc - shouldn't come across it on school PCs hopefully!! It's different to other keychangers - RockXP, Jellybean, VBS scripts, using the Windows Activation update key method etc - in that it will also fix up the PID of the Windows version, accept the key and get Windows to pass WGA correctly. This is not a 'dodgy' tool - it's an official Microsoft one.
Back story - given a laptop to fix up, someone had installed a 'corporate' ie. warezed version of XP Pro on it despite it having an OEM COA for XP Pro on it. Needed to clean spyware up, get it to pass WGA, install Windows Updates, install the new Security Essentials etc. I could change the product key in the registry with any of the key changers mentioned above but no joy on validating Windows - "The key your copy of Windows is running was not distributed by Microsoft".
Trying to force reactivation with msoobe didn't work either - dodgy copy of Windows would not accept an OEM key as valid (obviously) and the middle numbers in the PID for Windows in My Computer were the infamous ones. Thought I was going to have to wipe and reinstall a proper copy of OEM XP - a pain, since you then have to redo all their programs etc.
Downloaded the MS tool, ran, gave it the OEM key, it chugged away for a minute, requested a reboot, came back up fine - checked the PID in My Computer which now had OEM in it, went back to MS website, validated Windows perfectly. Whoo!