all games freeze my pc and force a reset.

So i have had this problem only recently. It use to just be the xcom games that froze the comp but now every game is doing it. The game will play for about 4 min and then a total system freeze. I flashed the bios and updated them as suggested when i had the xcom issue. That is what cause all my other games to do it too. Its not a heat problem because the gpu and the cpu never reach into the danger levels. I have no clue what to do.

my specs: Mother boad : gigabyte F2A78M- D3H Chipset: A78 FCH CPU: AMD Athlon X4 860K Ram 12 gig ( dont know the names) GPU: AMD Radeon R7 370 4G

I dont know what else you may need but let me know.