Games on external monitor on laptop problem

VladMtg - Sep 26, 2015 at 06:20 AM
I have a big problem with my laptop
I have an Asus x550j I7 and gtx850 but everytime i try to play games on my external monitor the laptop goes black or restarts .
If i try to play games like CSGO Black Ops II GTA V on the laptops monitor it works perfectly but if i play on my main external monitor i can play for like 10 minutes before the laptop restats or goes black .
First i though it was overheating because of the bigger resolution so i tried to play on the external monitor with the same resolution as my laptop's screen . But it doesnt matter i still get restarts or black screens . ( resolution on my monitor is 1080x1920 while on laptops is 768x1360 , and also i use a vga cable ) .
Can someone help me with my problem please :C ?