New pc build won't start

[Zuhair Ishraque]

My specs are:

Processor: Intel i3-8100

Graphics Card: NVIDIA GEFORCE GTX 1050

Power Supply: Seasonic S12ii 520w

Case: Dell OptiPlex 790 Mini Tower

Motherboard: GigaByte B360M DS3H MicroATX

Memory: Patriot Signature DDR4 2x4gb (8gb)

 

I connected all these parts together and I have all the cables in the right place. I connected the PSU's 24-pin connector to the motherboard and 2 4-pin connectors into the 8-pin slot on the motherboard. I have also connected my hard drive and optical drive. The case fan and CPU fan are all connected in the right places. My case fan's cable has 5 ports but only 4 of them have cables going into them so I think it's fine. I connected the cable to the 4-pin connector on the motherboard that was labeled case fan. Last night, I connected it all together and turned on my power supply switch. My power button isn't connected because it is faulty. It randomly shuts the computer on and off. I had been using the PSU switch to turn on my computer for the past year and it worked. It showed a screen that said "Power Button Failure, Press F1 to Continue" and I would press F1 and it would boot normally. Recently my motherboard got damaged and I bought a new one along with a new processor and RAM. My question is whether the computer is not turning on because there is no power button. I saw online that you can use a screwdriver and put it in the motherboard power button header pins and the computer will turn on. I also saw that if your motherboard is touching the bottom part of the case, then it will get shorted out, so there should be standoffs. However, on my case, there are elevated points where there are screw holes, and I connected my motherboard through them. I assume that there is no need for standoffs when it is like that because the motherboard is already elevated. The motherboard also fits perfectly with the I/O shield. None of my front panel buttons are connected because the slot on the motherboard and the pins on the cable don't match. This is not a problem because I can use the ports in the back of the computer. I am 99% sure that none of the hardware is damaged. When my parts were coming, I used my graphics card in another computer and there were no problems. I also haven't touched my power supply for the past 4 days and before that I used it and it worked perfectly, too. But then again, anything could happen.

[ELSknutson]

well yes you will need to jumper your computer with a screw driver between the power connectors but I would not use that case with out stand offs . it is set up for a dell motherboard  so adding a aftermarket motherboard that could have components that stick out further then the dell components. Also the area were you screw  in the board to the case could be different  or the pads could be smaller and could very much lead to shorting out your motherboard,PSU, etc. 

[Zuhair Ishraque]

4 minutes ago, ELSknutson said:

well yes you will need to jumper your computer with a screw driver between the power connectors but I would not use that case with out stand offs . it is set up for a dell motherboard  so adding a aftermarket motherboard that could have components that stick out further then the dell components. Also the area were you screw  in the board to the case could be different  or the pads could be smaller and could very much lead to shorting out your motherboard,PSU, etc. 

My new motherboard is actually smaller than my older dell motherboard. I read somewhere that you can still install smaller motherboards into bigger cases because the screw holes in the smaller sizes are subsets of the larger ones. My motherboard screws in with 5/8 of the holes. Are you sure I would need standoffs? My motherboard lines up perfectly with the I/O shield and if it went higher i don't think it would. Unless there's a way to not get it higher by still using standoffs, which I don't think is possible. The screw holes are elevated with little circular bumps so the motherboard doesn't actually touch the bottom of the case. It only touches the screw holes. The screws go in straight and fit perfectly, too.

[Zuhair Ishraque]

I am currently out right now. I will post a picture once I get home if it helps you to better understand the entire setup.

[Zuhair Ishraque]

I also have another question. Do any other cables need to be connected from the power supply to the motherboard in order for power to actually be flowing besides the 24-pin and the 2 4-pins that fit into the 8-pin?

[ELSknutson]

If I were you I would test it out side the case first  also If you must use that case you have to ensure that were the stand off bumps are there are holes to screw into  because if one of the bumps is just sitting under your motherboard not being used that is bad and you will short something out. 

Also my other worry in  that case is  component touching the stand off bumps  as see in this poorly painted picture. 

[ELSknutson]

2 minutes ago, Zuhair Ishraque said:

I also have another question. Do any other cables need to be connected from the power supply to the motherboard in order for power to actually be flowing besides the 24-pin and the 2 4-pins that fit into the 8-pin?

no assuming that your GPU is powered by the motherboard. 

[Zuhair Ishraque]

13 minutes ago, ELSknutson said:

If I were you I would test it out side the case first  also If you must use that case you have to ensure that were the stand off bumps are there are holes to screw into  because if one of the bumps is just sitting under your motherboard not being used that is bad and you will short something out. 

Also my other worry in  that case is  component touching the stand off bumps  as see in this poorly painted picture. 

Oh I see what you mean. Thanks for the info. I will check this once I get home and I'll update you on this.

[Artyomka]

Also try unplugging all of the fans but the cpu.

[Zuhair Ishraque]

2 hours ago, Artyomka said:

Also try unplugging all of the fans but the cpu.

I only have a case fan and the PSU and GPU connected to it. I unplug all of those?

[Zuhair Ishraque]

This is the picture of the motherboard seated. The three screen holes that are open aren't touching any metal part of the mobo.

[Zuhair Ishraque]

This is the picture of the motherboard seated. The three screen holes that are open aren't touching any metal part of the mobo.

[Zuhair Ishraque]

Sorry I posted that twice on accident. My computer's working. I just had to use the screwdriver to start it. All hardware is fine. Thanks a ton for the help.