I had this problem before.
If your game beeps when you start, you have the problem I had and here's how to fix it. If not, this is worth a shot.
Reset your game preferences in the AMD software. Go to game settings and remove your CS:GO preset. Then scan your system again for the AMD client to produce another CS:GO preset.
Thanks for the response callzumg! But i already tried and didn't work. Now i can't exit the game, the screen goes black and i have to reboot the system.
I will try to uninstall the game and install again. But i can't stop thinking it's a hardware problem of the graphic card...
I will keep waiting for other suggestions, but thank you for the help!
I'm at that problem too now. If I play on 16:9 and minimise my game or turn off the game, my whole PC freezes up and I have to hard restart.
My only fix around it is to play on 4:3 however I'm already used to this.
This is a problem I'd also like a fix for.