Computer Problems, Please Help

I'd like to start this off by saying i'm sorry if this isn't in the correct section, and head on to my problem.

Two years ago I built a new PC, all the parts were purchased in my country and everything here is very expensive. Everything worked fine with my old Nvidia 430 (It was just for a while, until I could save up for a normal GPU, don't judge me =]) Now when I replaced the 430 with a new Sapphire 7850 I had random crashes, and I thought it was a PSU problem, so I purchased a SeaSonic 860W platnium PSU, because of Crossfire intetions in the future. This fixed one problem, the other is still happening. Whenever I game after a while, it could be 10 mins or it could be a week at somepoint VGA signal will stop being projected to my main screen (the second one still works completely fine) and my speakers will repeat the last bit of noise made in the game over and over and over (for example if someone says the word "over" a very short part of the "r" will be repeated forever, until I restart) now for the last 4 months I have been working very slightly because I am in school and have enough money to either buy a new GPU, or a new Mobo/CPU/RAM, RMA in my country is not an option, which is why my next GPU is going to be EVGA, which I should be able to RMA, if need be. Please help me. ^^

Specs:

Asus Sabertooth 990FX

AMD 8150

Sapphire 7850 1GB

Seasonic Platnium 860w

Corsair Vengeance 32 GB

Put that 430 back in your system and test it again.

If everything works again, you have a faulty card.

I would purchase a card with at least 2GBs of VRAM in this day and age.

Problem is the 430 was broken when I moved, so I have no replacement. x.x