This all depends on how valuable the data is on this moved drive.
If the data isn't important then the best cause of action would be to format and reinstall windows with the appropriate drivers.
Having a second bootable drive in the system will have no detrement as long as you leave it out of the boot sequence, personally , once up and running with the other drive I would transfer all the important data front the now slave, to the new master, then format the slave and transfer the data back over onto the clean drive (not essential, just my opinion)
Martin
Replying helps further our knowledge, without comment leaves us wondering.