It sounds like the drive may be instrumented but not encrypted. Open a command prompt as Administrator. Navigate to C:\Program Files (x86)\PGP Corporation\PGP Desktop by entering this command:
cd "C:\Program Files (x86)\PGP Corporation\PGP Desktop"
Then run the following:
pgpwde --enum
That will tell you what the disk number is for the drive, then run this (where X is that drive number):
pgpwde --status --disk X
That result should show you if the drive is instrumented and/or encrypted, similar to this:
C:\Program Files (x86)\PGP Corporation\PGP Desktop>pgpwde --status --disk 0
Disk 0 is instrumented by bootguard.
Current key is valid.
Drive encrypted
Total sectors: 625139712 highwatermark: 625139710 reserved start sectors: 2
Failed login attempt lockout enabled. Max failures=5
Request sent to Disk status was successful
Post the results from those commands here or send them to me in a private message. If the drive is instrumented but not encrypted, you should be able to uninstrument the drive by running this:
pgpwde --uninstrument --disk X