HELP: PC Won't Turn On

[Plamy]

Hi,
My PC issue started a year ago: after Sleep or Shutdown the fans and lights remained active, i.e. don't turn off. Otherwise Windows 11 stops and the monitor goes blank as well. So I had to switch off the button of the power supply on the rear or to press the front power button for few seconds until everything stops. Since that time I had to run the system via power on, i.e. starting the PC, no more "wake".
Few months ago until now the problem went bigger: the PC simply doesn't start after pressing the power button!!!
Sometimes it starts every day during 1-2 weeks, sometimes it doesn't during 4-5 days. I disconnect it from the electricity for hours with power supply button on or off - that doesn't help. Sometimes the PC starts successfully and once running, everything is just fine as if as no any problem exists. Until Sleep or Shutdown, then not starting again.
Not sure if the power supply or the motherboard are the problem because when the PC is connected to the electricity, (even not able to start) the light diode on the motherboard is lit.
I've searched for solution everywhere and still no any idea how to solve this terrible issue. Removing and reseating RAM, HDD, etc. doesn't help too.
The power options, drivers, etc. are all ok, never played with them actually. So they are not the reason. I think the reason may be hardware. A friend advised me to disable the internal graphics card from the BIOS, no effect. Don't know what to do anymore.
Please for your help!

[TGAlex]

Check the cables that connect the front panel to the MB? You may have a loose cable, bad tips or bent pins. Especially the delicate power pins don't take much to bend. First turn off the PSU. Remove the power cable (it's the little cable that connects the front panel power button to the MB) and check the pins on the MB. If they appear ok, put it back on. Make sure it's all the way in and nothing is touching it. Don't apply too much force, it's quite delicate. If there is another cable even slightly pushing against it and it's not critical, meaning you can run the system without it (could be a front panel USB port), remove it and put it out of the way for now. When you're done, turn on the PSU and keep it on. See if you can turn on the computer every day for a month.

In any case, the front panel area is where I would pinpoint your problem.

[Plamy]

On 9/3/2024 at 5:37 PM, TGAlex said:

... the front panel area is where I would pinpoint your problem.

What do you exactly mean? The power button?

[TGAlex]

Yes, if the PC does not power on at all and that is an intermittent fault, and at the same time a potential PSU issue has been ruled out, then it has to be something related to the signal that's being sent to the MB when you press the power button. Sometimes it goes through fine and other times not. How's the aforementioned cable, have you looked?