After booting when the XP screen seems to hang, just pull the DVI plug from where it's plugged into and plug it into the other DVI. If it's switched to the other DVI port, this would show you. You could potentially just leave it plugged into the second port, although that one might not show you the BIOS setup screen or once you are in Windows you should be able to use the Windows display properties to point everything to one DVI or the other.
If it's booting to the component out, you could probably use that to get into Windows and then set the Display properties to point everything to the one screen.