I have Win XP on one HDD and Win 7 on another. Win 7 was installed later and ever since the new HDD has been installed I cannot boot Win XP. I do get a boot menu but upon selecting XP the computer restarts. This started happening only recently when I reinstalled Win 7; before that I could choose either OS from the boot menu. I do not understand what has changed to disallow XP from booting... Any suggestions?