Hello,
install a new 500GB HD and installed Win 7 worked fine. I decided I wanted to make it a dual boot system xp - 7 . tried installing xp after creating and formatting the partitions. Is it possible the HD is bad??
No, you must always install the oldest OS first, XP in this case. what happened is XP's boot loader overwote windows 7's boot loader and now has no idea how to boot win 7.