Question PC TURNING ON AND OFF DURING STARTUP

[Abraham R]

Something very annoying and worrying is that when I turn on my PC it turn off and on again until it finally gets started.
I always worry about keeping my PC clean, free of dust. This occurs only (and not always) during power up.

CPU: Intel Core i7 4790.
Motherboard: Gigabyte Z97 Sniper.
RAM: 16GB (2x8 Kingston).
Cooling: Thermaltake Water 3.0
Power Source: Cooler Master 700W
System: Windows 10 Home.

I've noticed that usually the motherboard startup with AO value but when the problem occurs sometimes shows "04" or another.

 

[Dark Lord of Tech]

Is fast startup enable in the BIOS?