Problem with your PC

Not long ago, during a game started tightly for this PC, and neither alt + tab nor the task Manager does not work and saves only restart the PC via the button on the system unit. Just say a PC in repair can not be attributed as small town and people who can inspect or repair the PC's. When I play everything slowly starts to fail and misiti. Textures cease to load and everything starts to be like a wax Museum, using these textures I once fell under the world. If someone thinks that the fact that the video card is overheating or percent just say processor is heated a maximum to 70-73 degrees, some may think that it is a lot and could burn the CPU, but the CPU has been running for 2 and a half years at this temperature, and problems with it previously, there was also thermal grease is changed regularly. Video card high heats up to 61 degrees. I noticed that when it hangs constantly, the hard disk is loaded on 100%, as I know about it when even the task Manager doesn't work? Very simple I look at a light bulb on the system unit when the computer just works on the example I see VIDOS on YouTube is it just flashing or is not lit at all when the computer freezes it just starts to burn. I checked RAM using memtest and no problems detected. I tried lowering the graphics settings in the games but it didn't help. Also sometimes it begins to focus the sound, for example I'm playing the same COP, I shoot from the WUA and the sound of the shot begins again a few times or I play any other game in which music plays, and the last sounds of music begin again. To be honest it sounds such a loop is quite scary and not nice. Forgot to mention that when it freezes a blue screen does not appear, if he appeared I would have looked the error code and went to look for the identification code on the forums it would simplify the search for problem with PC, but the screen does not appear.
If you're interested here are my PC specs:
Processor - AMD Athlon x4 840
Graphics card - GTX 1050 TI
RAM - 8 GB DDR 3
Hard drive - WD BLUE 1TB
The system 64 bit, Windows 10
Power supply 650 watts
I'm interested to hear other people's opinion about this, so be kind to write anything about my problem. Thanks in advance for your answer.