BSOD after motherboard/CPU upgrade

Hello all, I need some help in figuring out a problem with my Dad's System. I had him upgrade his mobo and RAM because I had an athlon XP 2200+ lying around that wasnt being used. So he bought the ASUS A7N8X and 512 DDR 400 memory. Anyways, I put the new mobo in and connected all the IDE cables and such..which I have done several times for several different CPUs. Now when I turn the PC on it loads up until it gets to the Windows XP loading screen and then a Blue Screen of Death appears which is unreadable because the system reboots directly after the screen comes up. It just keeps repeating this process over and over again even when I try to boot into safe mode. I have no idea what the problem is, I've tried to put my athlon 3000+ in, my video card, my ram and the same thing happens. This leads me to believe its the HDD, which confuses me because last night his system was running fine until I put the new mobo in. I did change all the IDE cables to the ones that came with the new mobo..perhaps it could be bad cables? I have to drive back to his house to get the old cables because I didn't bring them with me to my house and I'm going to replace them and see what happens. In the meantime however...any help/suggestions would be appreciated. Thank you.

So you've changed the motherboard & expected Windows to work as if nothing had changed ?

Try do to a Windows repair & for future reference, here's how you should've done the switch -> Swapping your board without so much as a reinstall

Ok thanks I'll try that...I only went about it this way because I've swapped mobos before without experiencing any types of problems... I'll come back with an update.