Sounds about right to me. You have an upgrade disc that cannot find the qualifying earlier version. This version must be present.
I have been in this psosition twice when upgrading from Vista, the earlier qualifying version has to go on first.
The earlier version of XP was almost certainly OEM, and you have changed the motherboard. That disqualifies the OEM version of XP, so you cannot reinstall that, even if you wanted to. So you cannot upgrade.
Only solution seems to be a new full version of Windows 7, sorry.
Thanks for the reponse.
Ventanas: surely if having xp was a pre-requisite for installation it shouldnt let me install windows 7 at all? I still have the orig XP disc so i just thought i needed it to qualify the license. Its a full XP Pro (though 32 bit)
rdave13: option 4 looked good but too late now. In his initial warning above optoin 1 he does say they allowed you to install win 7 without having to install xp first. Not too sure why option 1 isnt usable.