Thanks for the reply ko888, the chipset is different on the new motherboard, could this be the reason why it doesn't want to boot up? (I upgraded from an old Intel Pentium 4 chip to an Intel i5 750)
I'm also thinking that Windows XP might think I'm trying to install the OS on a new computer since it doesn't recognize the motherboard/hardware and shuts down during the boot process, but I couldn't find my old XP install disk to try and troubleshoot/reinstall.
Over the weekend I actually broke down and went to Frys to purchase a new hard drive and installed a fresh copy of Windows 7, and my machine is now running smoooooth. I can reference my old drive for storage, but still can't boot from it as a master, oh well.