I have done it before with w2k, but not with XP, it should work though, but its potentially dangerous and may not work.
And I think it depends on what version of XP you have. If its a non-corporate copy, I am not sure its possible due to all that crap about checking for hardware changes and making you re-register.
What I usually do it go into the device manager and remove every last device by hand. There is a certain order you need to do it as well, Do the system devices and the hdd controller last. Then reboot. XP will find all the new hardware devices and install them.
Again, I have not done this on XP, just W2K,. Do the above at your own risk. Definitely make an image of that drive before trying it if you want to make sure not to lose anything.