Question Sudden shutdown

[unplanned bacon]

So this was probably caused by trying to switch on immediately after putting the PC to sleep, but I thought I'd ask. I put the PC to sleep and realised I had something running that I wanted to continue overnight so as soon as it was off I clicked the mouse to wake it back up. It began starting back up, but did a complete shutdown so I used the power button. I got lights, fans and then it cut. A second later it boots itself just fine. I have an i5 4570, GTX 780, Z97 Gaming 7, 840 Evo and two WD HDDs.

What could cause this?

 

[Lutfij]

When posting your specs, always list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

 

[Fix_that_Glitch]

Do you have fast boot enabled? To make a very long explanation short. If you have fast boot enabled(windows not bios) and you use the power button to cycle your computer it disregards fast start up and does a full post up.

 

[unplanned bacon]

When posting your specs, always list them like so:
CPU: i5 4570
Motherboard: MSI Z97 Gaming 7
Ram: Corsair Vengeance 16 GB
SSD/HDD: 120 GB Samsung 840 Evo, 2 TB WD Black and 2 TB WD Green
GPU: Asus GTX 780
PSU: Antec Truepower 750 W 80+ Gold
Chassis: Corsair Obsidian 750D
OS: Windows 10

Answered in the quote

 

[unplanned bacon]

Do you have fast boot enabled? To make a very long explanation short. If you have fast boot enabled(windows not bios) and you use the power button to cycle your computer it disregards fast start up and does a full post up.

Fast boot is on in both windows and the BIOS (the BIOS has its own setting for it too IIRC)

 

[Fix_that_Glitch]

Yes fast boot windows allows you to start up without doing the bios checks, the bios fast boot skips certain checks during a full post start up.