Premiere recently starting rebooting, bad HD or motherboard?

I need some help figuring this out.



Background. I have 3 Premieres (2 active, one still new in box, never used)



premiere #1, upgraded to 2TB 4+ years ago, no issue



Premier #2, still stock 320GB drive. about a month ago, I upgraded it to a 3tb drive, only 2.2 usable. after 1 week of solid use, it started random reboots. thinking the drive had an issue, i put the original 320gb drive in, and all worked for 1-2 weeks, until yesterday, where it also started random reboots, so much that it would only stay on for 5 minutes before a reboot.



At that point I had assumed the original drive had an issues, and when it copied to the 3tb drive, it copied bad data, and thus I had 2 "bad" drives, as far as data.



So. I took the original drive from premiere #1, and copied it to the 3tb drive. Thinking I could put it in premiere #2, as a new drive, knowing I would have to start with the guided setup and software update since it is 4+ years old as far as software goes.



But that drive won't even boot up, it reboots after about 30 seconds of "starting up"



so does this sound like some odd HD issue, or a mother board issue?



I still have a 3rd premiere I can pull out and use, but I would need to activate it, both active premieres have lifetime service on them.