The GPU stress test causing shutdown points to the display adapter or driver.
What is the make and full model number of the laptop?
Does it have dual or switchable graphics? What is the GPU make and model and the installed Display driver version and date?
I gave you steps to test various display drivers including some things to try with them. Did you do all of those? They are here:
The Display driver is so important here that merely updating it is sometimes not enough. So let's try everything possible to get it working correctly:
First make sure you have updated the Display driver from the PC or Display adapter maker's Support Downloads web page for your exact model number, HP Serial Number or Dell Service Tag - from the sticker on the PC.
If necessary first remove the old driver using DDU https://www.wagnardsoft.com/content/ddu-guide-t... (not necessary with Microsoft Basic driver which is a placeholder if nothing else is available) and/or installing in Safe Mode with Networking (so you have internet), or Safe Mode, accessed by one of these methods: https://www.digitalcitizen.life/4-ways-boot-saf...
While there check also for newer chipset, BIOS/UEFI firmware (very important), network, sound, USB3 and other drivers, comparing to the ones presently installed in Device Manager reached by right clicking the Start Menu.
If this doesn't give you the latest or ideal driver for what you need, compare it to the driver offered by the Intel driver update Utility here: http://www.intel.com/content/www/us/en/support/...
or the Nvidia Update utility here: http://www.nvidia.com/Download/Scan.aspx?lang=e...
or the AMD autodect utility here: http://support.amd.com/us/gpudownload/windows/P...
For Display issues one fix that is working is to Roll back or Uninstall the Driver on the Display Device > Driver tab, restart PC to reinstall driver.
You can also try older drivers in Device Manager > Display device > Driver tab > Update Driver > Browse > Let Me Pick.
Then you will know you've tried everything in addition to Windows Update drivers.
Adjust the screen resolution until it fits and looks best at Settings > System > Display.
Check for a monitor driver by expediting Windows Updates (including Optional Updates) in Settings > Update & Security > Windows Update > Check for Updates to install all Updates until no more are offered.
Please report back answers for questions I asked and result of trying each of these steps again.