Coming from this thread (http://www.tomshardware.co.uk/answers/id-3690583/suddenly-takes-long-time-boot.html), I found out something happened to my Samsung 850 Pro making POST take way longer than usual.
It all happened after a BSOD:
Diskpart
Disk Management:
When I choose GPT it says "The specified disk is not convertible because the size is less than the minimum size required for GPT disks." and when I choose MBR it says "The system cannot find the file specified."
The BSOD happened on Apr 18 at 17:43:52 and these are the drive's recent events.
These are events related to trying to initialize disk
Gparted in Ubuntu can't see the drive. BIOS can't see the drive. I've tried a different SATA cable on a different SATA port in the motherboard. SeaTools can't see any drive. Samsung's HUtil doesn't even boot. Disk Utility from macOS in a bootable USB drive can't see the SSD.
It all happened after a BSOD:
Stop code: IRQL_NOT_LESS_OR_EQUAL
What failed: ntoskrnl.exe
Diskpart


Disk Management:

When I choose GPT it says "The specified disk is not convertible because the size is less than the minimum size required for GPT disks." and when I choose MBR it says "The system cannot find the file specified."
The BSOD happened on Apr 18 at 17:43:52 and these are the drive's recent events.

These are events related to trying to initialize disk

Gparted in Ubuntu can't see the drive. BIOS can't see the drive. I've tried a different SATA cable on a different SATA port in the motherboard. SeaTools can't see any drive. Samsung's HUtil doesn't even boot. Disk Utility from macOS in a bootable USB drive can't see the SSD.