Windows 10: "Why did my PC restart" error

I had to reset my laptop but this appears. How do I fix it?

:)

 

PC Randomly Restarting after installing new Ram!

Tried your suggestions, but still had a restart! Also ran memtest overnight (13 hours according to memtest) and had no errors! Also ran Passmark Burn in test for a couple hours testing everything and had no errors or restart. Could fitting the new ram have triggered something to go bad like my mobo or psu?

 

How to troubleshoot an error that appears only at Restart or Sign out?

I get an error pop-up error message not every, but almost every time I Restart or Sign out. It's the screen with blue background and on top of Restart or Sign out text an error window says:

Explorer.exe - Application error. The instruction at 0x000… referenced memory at 0x000... The memory could not be written.

Sometimes the error code is just zeros, sometimes random numbers. I have tried so much already to troubleshoot this. For example these did not help in any way:

• MemTest86+ (no problems)
• Disabling any Services, Autoruns/ShellExView entries
• Low resolution mode
• BIOS settings are fine, no overclocking etc.
• DISM.exe and sfc
• etc.

However, these do make the error go away:

• End process for explorer.exe before Restart or Sign out
• Safe Mode
• Creating a new user profile (almost the same as clean installing Windows, many full days of work)
• Uninstalling NVIDIA graphics driver (then the card is unusable, of course)
• Disabling Device Manager / Display Adapters / NVIDIA GeForce GTX 1080

I already contacted NVIDIA and the graphics driver is not the culprit. Something has gone wrong with the user profile as the same driver works just fine in a new profile (and there's nothing wrong with the driver anyway, it's just the Restart or Sign out process that has a problem).

What can I do to fix this? One useful thing would be to have a step-by-step procedure for the Sign out. So that it'd ask before continuing to the next step and list what it's doing. Or if I could just disable whatever it does when the error appears.