Moving data with it being on a hard disk is a sorry road with many stories. There is some method of rewriting the MBR as noted at this discussion ->
I leave it to you to ponder if this is safe for your setup.
I recently replaced a 30 gig HDD which was the primary boot drive, I set it to slave and wanted to use it as a second backup. In disk manager, Win-XP the drive appeared and listed as healthy (active) but no drive letter .the only management choice was to "delete partition", it appeared in device manager and the setup screen as working properly. There is information on the drive I would like to keep but it is all replacable. I removed the drive and put it in a shell (as a master) so it could be an external drive using USB. I hooked it to another XP computer and got the same result so its appears to be drive oriented. How can I get windows to give the drive a letter when the only choice is to delete the partition?