This is a complicated question and I will try to get it right. Background: My old hard drive was acting up-rebooting over and over again. My computer was a few years old so I decided to buy a new computer and then take my old hard drive out of the old computer, put it in the new computer as a slave, and then retrieve all of my important data from the old one simply by copying to the new computer's hard drive. I would then reformat the old drive and use it for storage, etc. I got the new computer, an HP with XP pro, a dvd burner, media slots, usb 2, IEEE 1394, and a 150 gb hard drive. It works fine. I tried to put the old hard drive in the computer jumpered as a slave and in the slave position on the cable with the DVD as master. when I try to boot the computer it goes to my old drive first to look for an operating system and starts rebooting over and over again as it did before when I had the drive in my old computer. I tried putting the drive on a seperate flat cable as slave but it was looked at first for a system there too. I have verified that the jumper is in the right place on the drive but it won't act as a slave. the computer keeps going to it for a system before going to the good hard drive in the new computer. What am I doing wrong? How can I make my old drive into a second drive without erasing it and losing all my data?