If you installed Windows 8 with both drives connected, the Windows 8 boot loader is managing the bootup process for both drives. Removing the drive with Windows 8 on it must have completely messed it up. I haven't used PCLinuxOS before (I have very little Linux experience overall), but perhaps you can use the PCLinuxOS install media to reinstall its boot loader instead of it utilizing the bootmgr in Windows 8? If that's not possible, you're either going to have to reinstall the OS altogether, or put the Windows 8 drive back in temporarily and figure out a solution from there.
Edit: To avoid this problem in the future, if you want to install multiple operating systems on the same tower, disconnect all of the hard drives from the system except the one you want to install the OS to. For example:
Drives A, B and C exist in the system, each one will get an OS (OS A, B, and C). Disconnect drives B and C, install OS A to drive A. Once done, disconnect drives A and C, install OS B to drive B, etc. Repeat this for however many drives and operating systems you want.