Question All pc peripherals turn off but pc still runs!?!?

[ABRAkadABRA]

So i used to have a occasionall blue screens but this is a new problem it just started today and it happened 3 times so i checked to see any answers and explanation s but couldn't find them.

After about 10 min monitor, mouse, keyboard, speakers turn off but pc continues working and i whanted to see will it restart or turn off by itself but it doesnt.
I checked cables restarted it cleaned it same problem after about the same time of using it.
I never had this problem so i hope somebody has an answer quick i have a exam i need to study for.

Thank you

Specs
R5 2600
Gtx 1050
Msi b450 tomahawk max
Evga 500w psu
2x4gb ram hyperx

 

[Ralston18]

When you cleaned the computer did you double check that all connections and card seatings, RAM,and jumpers are all fully and firmly in place?

Look in Reliability History and Event Viewer for error codes and warnings that are logged just before or at the times of the problems.

How old is the PSU?

 

[ABRAkadABRA]

Sorry i didn't have time yesterday to see if someone responded.
Yes i checked everything is connected all the way and correctly.
Psu is about 4 years old.
Reliability monitor doesn't show anything out of the ordinary yesterday when it first happened.
But event viewer shows a lot of errors but thats nothing new ,like I said yesterday was the first time it happened but there are same errors days before yesterday.

Thank you

 

[ABRAkadABRA]

Ok im confused i turned it on to check the things you recommended and then whanted to see for how long will it run correctly and i even played assassin's Creed origind which is quite demanding for my pc, and now im playing some csgo i will write if i encounter any problems.

 

[ABRAkadABRA]

Ok so i was using my pc about 8 hours and problem came back so i guess that happenes when i use it a lot but i checked nothing is overheating