Solved Spontaneous restarts resulting in eventual blank screen.

My pc recently started spontaneously restarting (as in as if the reset switch had been pressed), seemingly at random in the last few days, until eventually while I was trying different possible solutions it stopped displaying the motherboard splashscreen at all and is now completely unresponsive. No beeps either, but it never did beep on startup.

I don't suppose this could be something simple like needing to replace the CMOS battery, could it?

While it was restarting I tried various power setting suggestions in windows, and also disconnected the power and reset switches in case they were responsible. Then when it no longer booted up at all I tried unplugging all non-essential usb devices, reseating the memory and graphics card, and even resetting CMOS.

The next thing I will do is get hold of an adaptor to allow me to view my main hard disc from my laptop and at least recover the last few days' worth of work that I did between this failure and my last backup, but before I resort to buying a new motherboard and/or anything else, I would welcome any suggestions. Thanks!

My PC spec is as follows:
Gigabyte motherboard 970A-DS3P
AMD FX 8350 CPU
Sound Blaster Audigy Rx sound card
NVIDA GeForce GTX 1050Ti graphics card
32GB Ram
Windows 10
700W Power Supply

Thanks for your response. The PSU is
iChoose Limited Switching Power Supply PSU 700W ATX.

It may also be useful to know that I built this PC in May 2019 and have used it consistently since then with all of the same components.

Also when looking up my purchase of the components in order to get the model number of the PSU I read one customer review just now saying this PSU has a habit of failing during power hungry processes.

This seems relevant except my system and usage habits haven't changed in four years, except for adding a few USB devices, which I connect through an externally powered USB hub.

Anyway I hope that helps. If it is the PSU I would be very grateful for a specific recommendation of a new PSU model to use instead. Thanks again.

Thank you. Could a good enough PSU mean that everything runs normally again? I am very worried about not even seeing the motherboard splash screen at all. I hope that doesn't mean something has been damaged.

Thank you very much. I have ordered a better looking PSU on Amazon. If it isn't the answer I will be able to return it. Fingers crossed 🤞🏻.

I swapped in the new PSU last night. Cooler Master MWE 850 Gold V2 Fully Modular PSU (only a 5 year warranty, but I had already ordered it by the time I saw your post).

When taking out the old one I believe I discovered the problem. The connection between the four-pin plug from the PSU and the extension cable I was using in order to reach the corresponding socket on the motherboard had bad burn marks on it. I don't know if I should consider myself lucky that the extension cable saved the motherboard, or if the extension cable is to blame. This new PSU reaches everything without the need for any extensions.

Meanwhile my PC is running just as it was before from the new power supply. I will be sure to look for one with a longer warranty next time, but at least this one has much better reviews.

Thanks again for your help!