technical problems

My system is locking when turning heavy games. GRID AUTO SPORT, FIFA 2017, PES 2013, NEED FOR SPEED and so on. The OS is W 7 Ultimate spk 1, i7 3770, HD 1T, 16GB MEMO, AMD HD7770 1G DDR5, CORSAIR 500W Power Supply. If anyone knows anything about this problem and can help, thank you in advance !!!