Computer won't turn on at all. Dead Cpu/Motherboard?

[NightSurge]

So my parent's computer won't turn on anymore. Originally was thought to be the power supply, so I took out the PSU and tested it with one of my PSU testers and it turned on, and all voltage readings looked spot on.

I tried removing the motherboard from the case to see if it was a grounding issue, still didn't turn on. I disconnected everything but the main power and CPU power, still won't turn on. I tried turning it on without the CPU installed and it still won't turn on.

Will a computer still turn on without a CPU installed? Surely it would at least power up the fans and whatnot if the mobo was working, correct?

I have tried everything short of taking apart the power switch on the case itself but from close inspection that looks fine as well.

Is there any way to know for sure if it is the motherboard that is at fault or cpu?

 

[MindoverMaster]

It will not turn on without CPU. I think if CPU was bad it would just turn on and shut off.

 

[NightSurge]

That's what I figured, but I wasn't sure so I tried it anyways. So technically the CPU could possibly still be bad? It would be much easier to fix if that is the case. No matter what I've tried with the CPU installed it still won't turn on or power up the fan I have connected to test it.

 

[MindoverMaster]

Could just buy a new motherboard/cpu combo...

 

[NightSurge]

Yeah, I was hoping to narrow it down to just one or the other if possible. They want to spend as little as possible on the repair and need it back ASAP.