New motherboard, old hard drive, problems..

I have a new motherboard that as an AMD64 3200 processor and I had to add a nVidia video card. My previous motherboard was a Pentium 4 with an onboard VGA. When I attempt to connect the old hard drive to the new motherboard I can load in safe mode but I get a stop message when I do a normal windows XP SP2 load. I installed the nVidia software in safe mode but still no luck. Any ideas about how I should proceed from here? It’d be appreciated.