@scarabs, I suspect that the ASRock utility has overwritten the beginning of the file system on your external drive. I would stop and take stock of the damage, and then formulate a plan of attack.
To this end I would use a disc editor to first examine sector 0 of the HDD. If you could upload the contents of this sector, then we may be able to determine what happened.
Roadkil's Sector Editor:http://www.roadkil.net/program.php/P24/Sector%20Editor
HxD - Freeware Hex Editor and Disk Editor:
DMDE (DM Disk Editor and Data Recovery): http://softdm.com/download.html