Really, if you follow the instructions that your manufacturer (for the motherboard) supplies, and look up some stuff online to better understand the process, it's not going to be hard to flash your BIOS to upgrade the version.
I also have a suggestion for your problem with needing XP: Can you run a virtual machine of XP inside Windows 7 and use what you need? That seems like a good idea, although I'm not sure what you're trying to do, so you may have a hard time doing it, but it'd be worth a try no?