Windows 10: Windows 10 shuts off at random times- but also during startup

This problem started yesterday;First, I booted up my PC, but before anything shows on the screen- it fails and simply shuts off. later the day, it did the same thing but while I was playing.Today it happened again while I booted it up, several times until I unplugged it from the power, waited a few seconds, re-plugged and it booted up normally this time.I tried accessing the event viewer to see what exactly happened that made it crash, though I couldn't find a reason for the crashes..The crashes seem to have no pattern other than when I boot up the PC, I would very appreciate a solution..

:)

 

Can't get GPU-Z to start with Windows 8.1 startup

I'm not sure how to do that. Could you list the steps for a noob?

 

HP Pavilion 15 randomly shuts down incorrectly if fast startup enabled

I've just updated an HP Pavilion 15 from Windows 8.1 to Windows 10 (Home 64 bit). If fast startup is enabled, the laptop freezes at the very least step of the shutting down process. The shutting down process goes like this:

1. First you click on shut down
2. The shut down screen appears
3. The screen turns off and then the fan starts to spin at high speed
4. After 4-5 seconds, the fan stops
5. The laptop is completely turned off, no lights are turned on (in most of PC's)

Well, my problem is that randomly, the Pavilion 15 freezes after step 4 has been completed, with the light of the ON/OFF button turned on forever. Sometimes it turns off correctly, but many other times this happens. If I disable the fast startup, this won't happen and it will always turn off correctly.

What can I do?
How is it that it's random?

I've tested this with no apps running on background, so that can't be the reason, besides, no apps or programs can freeze the system after the step 4 has been completed, since they are all shut down after step 1.

Also, the fast startup option was activated when I was using Windows 8.1 and never had a single problem with this laptop.

 

Is it time for Windows 10 already?

Here's a good step by step guide on doing a fresh install.

How to clean install Windows 10 from a USB drive - Software - Feature - HEXUS.net