Question PC randomly restarts


Oct 23, 2016
It's been a few years since I built my first PC (many thanks to the community here for helping me with that).

Recently, there have been a few issues with it. I do not know if they are related, but I will list them all in case it helps diagnose my main problem:

1) Sometimes my computer randomly restarts. This only seems to happen when I play demanding games.

2) Sometimes the games I'm playing will randomly turn off. The PC keeps running so I can restart the game.

3) My PC used to start up incredibly fast. Now I get a black screen with a blinking white cursor, and some whirring noises, for a few seconds every time I start it up.

I'm aware "My computer randomly restarts" is probably not enough for a diagnosis. If you can recommend any steps I can take to work out what's causing this, I'll take them.

Motherboard: ASUS Maximus VIII Hero
CPU: Intel Core i7-6700K 4.0GHz Quad-Core Processor
CPU Cooler: Corsair H110 94.0 CFM Liquid CPU Cooler
Memory: Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-3200 Memory
Storage: Samsung 960 PRO 512GB
Video Card: Asus GeForce GTX 1080 8GB
Power supply: Corsair AX860 ATX
OS: Windows 10
Random restarts normally indicate a PSU issue. How old is the AX? You can try swap it out if you have another, or bring to a local repair store and get them to swap out and test.

Although the AX860 was a quality PSU in it's day, it may be failing.