Not exactly, nat1, in fact, quite the opposite. Once you remove (delete from disk) any boot driver, windows XP treat this situation as if the operating system is unbootable (since boot required driver is missing) and stops the booting with BSOD. So you must be sure not to remove the sys files from the disk until they are uninstalled (removed) from the registry.
We are talking about C:\Windows\System32\Drivers\ folder, the one you are mentioning in config.nt is just for the DOS emulation and does not have any importance during system boot.
So if you know that some driver required during boot (be it mup.sys or other) is missing from your disk, (windows\system32\drivers folder) I recommed copying it back from your installation CD. You might also try the recovery option on the Windows XP instaltion CD, it works quite often as well.