rondog 0 Newbie Poster

I have a dell ins 1501 recently upgraded to 320 gb hard drive. used the old hard drive to load windows xp on so I can use some older programs that I have. Problem is that my laptop won't boot the xp system. Tells me I have a fatal error. any tutors out there that can tell me how to boot a second operating system from a usb/sata wire hard drive?