PC won't boot unless restart button is pressed 15 seconds after the power button

[jay_smith]

Ive had my PC for about 3-4 years second hand and the first thing I was told is that it wont boot unless I press the restart button 10 seconds after the power button. Over the years this has increased to 15 and I just assumed it was normal and didn't look into it. If I don't press restart in 25 seconds then the PC turns off then on again and stays running but not booting. If I then press restart at any time it boots but makes me press f1 to fully boot. I have tried googling the issue but I have no idea how to phrase the problem so nothing relevant comes up.
If anyone had any ideas on how to get it to boot just from the power button that would be great,
Thanks

Edit: One time it booted fine from me pressing the power button. I did nothing to change it and it never did it again.

Specs
PSU: Corsair CX750
CPU: Intel Core i7 920
Motherboard: EVGA x58 Classified 4-Way SLI
RAM: 16GB DDR3 ( 2x4gb Corsair Vengence + 4x2gb Corsair Dominator )
Graphics card: NVIDIA GeForce GTX 1060 3GB
HDD: Seagate barracuda 1TB

 

[150760]

Did you buy it from someone? Home made? Or from a store?

 

[jay_smith]

Did you buy it from someone? Home made? Or from a store?

I bought it second hand and from what I know he build it himself.

 

[150760]

He could have misplaced the SW-restart and the SW-Power pin cable connected from the power button into the motherboard. They are located on the bottom of your motherboard. 2 cables called SW-restart and the SW-Power are connected they are labeled and you have to put it in the correct order. I cant find any info on what the connector labels say label placed on the motherboard where the pins are connected there are different sections.

 

[jay_smith]

He could have misplaced the SW-restart and the SW-Power pin cable connected from the power button into the motherboard. They are located on the bottom of your motherboard. 2 cables called SW-restart and the SW-Power are connected they are labeled and you have to put it in the correct order. I cant find any info on what the connector labels say label placed on the motherboard where the pins are connected there are different sections.

If they were in the wrong order, would the restart button act as the power button and vice versa? Becasue they both work as intended when the PC is running.
Also, when I got a new case I plugged them into where the lables say but it didnt change anything.