May I suggest since you have separate HD's that you use the best method in that case which is to boot via the BIOS.
Keep the preferred HD set to boot first in BIOS setup, then when you want to boot the other HD tap F11 ASRock one-time BIOS Boot Menu key to boot the 250gb HD instead.
You may need to reinstall XP as there is no content showing on the 250gb HD. If confirmed and you want to use the BIOS Boot method, then during XP install unplug Windows 7 HD and set XP HD as first to boot in BIOS setup.
Since you had Ubuntu on that HD previously, it should be wiped first before installing XP using DISKPART Clean All command from from Windows 7 elevated Command Line: Disk - Clean and Clean All with Diskpart Command
Then boot XP CD to create and format partition(s).