Problem #1 is you say you have an OEM copy of XP and that you're changing the motherboard. That won't work. The license for the OEM version of Windows lives and dies with the hardware it was activated on. According to Microsoft's way of thinking, and since they control the activation servers, theirs is the only one that counts, what you're doing basically constitutes building a new computer, so you need a new Windows license for it.
Even if you get past where you are now, it will fail to activate and you will get nowhere with the phone reps in Microsoft's Activation Center.
So I would just cut my losses were I you, and rethink the whole setup. Based on what you've described, I already know what your problem is, but it wouldn't matter if I told you how to solve it. Odds are installing Windows is beyond your current skill level, especially since if you're replacing the motherboard you're probably going to be using a SATA HDD, which adds a whole new level of complexity to what is already more than a lot of people can manage.
I am in the process of upgrading APU, Motherboard and power supply in my CPU operating Windows XP Pro/3.
I have read the typical install tips about replacing a motherboard but have hit a problem. I inserted my OEM CD and after clicking Install XP, I get an error message that tells me the installed version is newer than the one on the disk. Is this because the CD has on Service Pack 2 installed on it and I have Service Pack 3 on my computer? It is the CD which I installed the OS in the beginning. Do I proceed with the upgrade?
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