|Like Jam said, the boot files are on your win98 drive, if you move it, the system will not boot.|
Even if it did, nothing would work, because you cannot change an OS's drive letter. The system's Registry's settings all reference the drive letter that the OS was installed on, changing the drive letter makes all those references invalid.
Operating system drives cannot be moved!!! The Win98 disk will only work as C:, and the Win2K will only work as D:.