Well, if youre replacing the boot drive, of course you have to reinstall everything, but if youre just putting in another hard drive, there shouldnt be any problems. A few more details on your exact problem would be nice.
In any other windows you could clone the hard drive. No problem. Don't you think they should have incorperated it into XP. Like no one's going to upgrade there hard drive. Don't you think they should have thought about it? And yes I meant Windows XP was my OS. Not that the computer was running at the time.