I had an HP laptop that had a fried motherboard and I had sold that one for parts. I kept the hard drive to retrieve my stuff on it. Recently someone gave me an HP laptop that the hard drive was damaged in. The hard drive mounts up fine and I was wondering if there was a way to boot up off this hard drive without having to buy a new operating system. I mounted it and had no luck. I was just wondering if this was even possible and if so what i might do to make it work. I believe the computer had Vista and the HD has XP. I know it's obsolete but we were just looking for a spare laptop. Thanks for any help.