Newer SSD drive disappearing and reappearing

[Heywan]

I am using a relatively new Samsung 850 Pro (512GB - 5 months old). Until recently I have had no problems. The past week it has been randomly coming out of sleep, and Windows 7 seems to be refusing to update. When I hit shutdown and update, it just shuts down. Same for restart. I don't know if these are related to my current problem; thought they might be.

Today I started my computer, left for a bit, and came back to a "Reboot and select proper boot device" screen. So for some reason the computer restarted itself and lost track of the SSD. When I booted to the BIOS it did not see my hard drive at all. I tried booting from my install CD, and it saw the drive. Went back to BIOS, drive still invisible. After restarted a few more times, it showed up in the BIOS again and I was able to boot to Windows. Great, but what changed? I did nothing and it seemed to "fix" itself, which makes me nervous.

Am I on the verge of hard disk failure? Could it be a BIOS problem? Maybe Windows needs a repair? How can I diagnose this problem?

Edit:Ran CrystalDiskInfo and it gives me a 100% health status. Ran Memtest86 to see if it was RAM, no issues there either.

Edit 2: Ran CHKDSK and it said it discovered free space marked as allocated in the volume bitmap. It noted that it fixed that. That wouldn't be the problem, would it?

 

[JohnBonhamsGhost]

check SATA & power cables. they can come loose and cause these types of problems.
Windows can have these types of issues inside the OS but that wouldn't cause your motherboard to not notice the drive at boot.
some worse case scenarios; it could be the motherboard's SATA controller going bad or could be the connection on the SSD itself.

the best way to troubleshoot the drive is to try it in another system and see if it has any trouble being detected over 10-20 restarts.