I think you will have more luck mounting the drive horizontally... that way the bumps don't throw the heads in other places... I changed mine and found that it was much more robust against the bumps in the road. But if your puter is restarting, you may not have a HDD problem. It sounds like either a wire is loose and is resetting the motherboard. (Even a wire that doesn't go to the motherboard could cause that). If not these, you may want to check heat problems next.