Computer won't boot or post. CPU or Motherboard issue?

[ranadeepmitra21]

My computer refuses to boot or POST. It was working fine a couple nights ago and the day after, pressing the power switch just caused the fans to spin for a second and stopped. So far I have tested the motherboard without the RAM, tested the power switch, and tested the power supply. The speaker will not beep at all. I did this all yesterday and gave up. In the middle of the night, I woke up to find the computer running. All the fans were on apart from the GPU, which was not running as there was no video output. I was able to shut off and turn on my computer and my motherboard beeped each time. I have no clue what caused it to turn on, nobody had touched it. It was very early in the morning so I shut off my computer and went back to sleep. I woke up this morning and had the same problem as earlier. At this point, I am worried it is either the motherboard or the CPU, but I don't know which and I have no compatible alternate parts. Is there a way for me to figure out if it's the CPU or the motherboard is faulty? I ran power through the CPU fan to see if it was working and it was, so I don't believe it overheated. I don't want to spend money on one without knowing which is faulty. Also pardon my ignorance on the matter, I'm not the best when it comes to building computers but I am trying to learn. Thank you.

 

[lachiu]

Have you tried another psu already? You should also try all the things in this list.

 

[doh]

As part of the check list you should buy and connect a new system speaker, in case your system doesn't have one or it's broken.
Have you got built in graphics capability ? If so remove you graphics card. Or try an other one (which should of course) be compatible) [borrow one ?]
That your PSU appears OK is no guarantee that it is functioning adequately under real conditions - i.e., with the system load as opposed to the st conditions, which are almost invariably under very low load conditions. (but it's a good sign that your PSU passed your tests)
Also, disconnect the power, and hold the power button down for 30s. Some things to try are disconnecting all components (PSU, graphics card, HDD) [see precautions for doing this safely] and reconnecting them.
Apologies for repeating anything in the fault finding guide.

Doh!
30.May.2018