You said you have two video cards, so hopefully you don't have both of them plugged into AGP/PCI slots at the same time while trying to install Windows
Anyways, I would suggest that when installing xp, remove everything that is in a PCI or AGP slot so as to reduce the amount of items that could be causing the freezing. I would also suggest that you take out the RAM that you bought and blow into the slot on the motherboard where the RAM goes.
As gerryf stated, using a standard ps/2 mouse and keyboard would be better, but check in the bios and make sure that USB support is enabled, because that could be causing the freeze up as well.
Just a couple of things for you to try, hope one of them works