I recently purchased an HP envy 750-427c. I wanted additional storage to migrate my old failing HP laptop. I ended up havein to reinstall windows from scratch (my bad) but now I have a clean install when I add the second drive it sees it as a USB removable media device. I have gone through the whole exercise of MBR to GTB configuration. The BIOS sees the drive fine but windows will only show C drive and the drive manager shows it as removable media. When I move the drive to an external dock on my laptop it sees it fine, I can format and partition the drive without a problem. I will add some screen shots since I am writing this on my lap top not desktop machine.
I Thought I had added these screen shot but I didn't, operator error. The drives are the orginal HD that comes with the desk top and I added an HGST deskstarnas 4T 7500rpm with 128 MB cash. I did swap the SATA cable and the result is the same. I guess the gbt format really threw me it has been some time since I tried to add to a system and I have some catch up to do. Thank you for the reply. Hope this info sheds some light.