Question Computer wont boot after installing 2nd SSD

Sep 18, 2019
I own a MSI GP62MVR 6RF laptop with a preinstalled HDD and a 960 EVO PCIE that I installed that houses the OS.

Last week, my laptop had an I/O issue with HDD, when it could access the drive until I rebooted. Fearing that the drive was dying, I purchased an 860 EVO to replace the drive.

When replace the HDD with the 860, at first the computer wouldn't let me initialize it as a GPT, so I used MBR instead. Then, I couldnt format the drive due to an I/O error. So from suggestions online, I purchased an SATA to USB cable and hooked up the 860 to my computer that way. I used Samsung's data migration tool to clone my old HDD onto the SSD. When hooked up to the USB, the 860 showed up as a GPT drive formatted to NTFS.

When I removed the HDD and replaced it with the 860, windows would refuse to boot, eventually giving me a BSOD and an inaccessible boot device error. Either that, or I'll log into my windows and it'll immediately crash. Only once did I manage to load in correctly and everything seemed to be fine (after switching back from RAID to AHCI), but even then, my Samsung Magician did not recognize the 860 as a Samsung SSD. When I tried to restart my computer, windows hung on the restarting screen. After that, I've never been able to boot into windows.

I checked my BIOS and it stated that my 960 was my primary boot device, not the 860, but no matter what kind of configuration I tried in my BIOS (UEFI/legacy, AHCI/RAID), Windows would not boot.

I then removed the 860 and replaced it back with the HDD and Windows booted fine, and I tried booting with the 960 by itself and it was still fine.

Since then, I've tried cleaning the 860 and reformatting it through diskpart, but the computer will still not boot with the 860 in it. I've also made sure that my BIOS was fully upgraded, and used Seatools to check the state of all my drives and they all turned up healthy.

I'm wondering if theres a problem with the motherboard's SATA port, but the computer reads and writes perfectly well when the HDD is attached.