Since your symptoms seem to change and you have a psu coming swap that first and test.
If no help remove the gpu and plug the monitor into the mobo also remove one stick of ram and test.
Hello All,
I have been experiencing computer some computer issues to which I'm asking if anyone is up for helping a new hardware person.
My pc turns on but does not boot up...sometimes.
I press the power button, and it turns on, I see lights!
Then, before anything can be displayed on my monitor, Its already off.
Only on occasion does it boot up completely and I maybe have enough time to send an email before shutting down. (about 2 out of 10 times roughly)
After some troubleshooting (e.g. dedusted the tower, took out PSU and all plugs, also took out GPU. Then plugged all power back in) it was able to boot up and seemed to perform as normal while staying on for nearly 3 great work efficient hours. (and continues to operate for an extended period before randomly shutting down.)
During my procrastination watching YouTube the computer precedes to say, “shutting down” and precedes to turn off as if I went to turn it off myself.
I'm not sure if this is a PSU problem, a motherboard problem, or a bad 24 pin connector or really anything else. I am in the works of acquiring a PSU to see if it might work.
In the meantime, any suggestions or thoughts? Anything will be appreciated to a new comer.
Ps the processor stayed within a normal range of 25C°- 38C°
Setup:
Intel - Core i5-6600K 3.5GHz Quad-Core Processor
Asus - Z170-A ATX LGA1151 Motherboard
Corsair - Vengeance LPX 16GB (2 x 8GB) DDR4-2133 Memory
Noctua - NH-D14 65.0 CFM CPU Cooler
MSI - GeForce GTX 1060 6GB 6GB GAMING X Video Card
EVGA - SuperNOVA NEX 650W 80+ Gold Certified Fully-Modular ATX Power Supply
And of course, Win10 64-bit

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic