The computer is a Compaq that was purchased new from Frys approximately 3 years ago with Windows XP Media Center Edition 2005 installed on it. It has never had a installation of XP Pro on it (I don't even have access to a copy of XP Pro). I created a partition on the HD to install Windows 7 when it came out, and have a 'Previous version of Windows' option in the boot menu to boot to the XP side.
I recently upgraded the motherboard and when I boot into XP it says it must be activated. I had to use the phone option as XP doesn't make it to internet connectivity (irritating). I called phone support and was told the 'Installation ID' that it created is a 'Windows XP Pro' id and is not a valid key. What now?