Thanks for your reply.
I have run Check Disk with all options, no errors reported. Other things I've tried:
1. Complete Virus and Spyware/Malware scan in Normal and Safe Mode: Negative.
2. Repairing my installation of Windows
3. Moving the SATA to another port on my Motherboard
It's an odd situation: I can access the disk; but I need to right-click and select "Explore." If I try to double-click, I get the error posted above. I get no errors double-clicking my main HD.
It's almost as if there is some registry file or something that's missing, but I have no idea what.