Why is my PC restarting on its own?

Question

Iron

Conf:
i5-2400, gtx 750, 4 gb * 2 ddr3, hdd - 1tb WB blue, ssd - 250 gb WD blue. BP 500w.
It all started a couple of days after buying an ssd drive. PC randomly shuts down and immediately turns on . The temperature of the processor does not rise above 50, for ssd - 35-36 *, hdd is about the same.
Moreover, this happens regardless of whether there is a serious load or not. It rebooted in the same way in the BIOS (just running). Tried to change connectors/wires, no results.
Also, the first reboot occurred after the last update in windows. Not sure if this is directly related, but maybe someone else has this problem?
What could be the problem and can it be fixed without taking it to the store?

Answer 1

If possible, remove all intestines from the body.
There was such a case when the motherboard shorted to the case and the PC rebooted due to a short circuit.

Answer 2

PC randomly shuts down and immediately turns on

There is a high probability of a problem in the PSU, as Artyom said - the capacitors have dried up. The motherboard itself restarts much less frequently, although the conders on it can dry out, only the symptoms are different.
And in general, there are Windows Magazines - read, don't be lazy!

Answer 3

It is quite likely that something is shorting or heating up (I'm not only talking about the processor), but the BIOS has an auto-reboot when it is turned off incorrectly, so it gets mad, and also with what frequency it turns off, how long does it work after turning it on?