Cs:GO Problem

[leniveca]

Hello everyone, 

I see many post about Black screen and sound loop in cs;go , but i didnt see how can i fix it ...
The problem is:
im playing cs;go and after 3-4 competitive matches (like 30 40 min per match) my game starts to randomly back screen and sound loop for like 3-4 sec and then its ok everything is working fine until crash again . I lost like 2 week to fix that and i still cant ...

What did i try:

CS:GO Game reinstall
Verify game cache
Remove all old registers and drivers (NVIDIA)

Installed last drivers
Installed last drivers ( Raltek )
I do stress test on my GPU ( 99% usage for 50 min = 76* ) 

Stress test CPU ( thats the strange - 100* no the stress test )
Clean my pc 
antivirus scan

 

My PC CONFIG:

Processor: Intel core i7 4770

Video card : nVidia GeForce GTX 770

RAM: 8GB
System type: 64 bit
OS: Windows 7

 

I will be so happy if you tell me what to do . Im not reistalling my windows only and is it strange that i get 100 degrees temperature on my stress test CPU (i dont know where did i download my stress test cpu) and i remember that i put it on normal setting before the test... So i check my temperatures after 3 HRS playtime 
they was: 75* - CPU and 65* GPU

Thank you !
Bless you !