Crash when using nVIDIA card

[i-ongei]

Okay hi.

So I've had this laptop for almost around 2 years now I think. Its not really that much of a good one its a Dell Inspiron 5558 with Intel HD Graphics 6000 and for dedicated its got a nVidia Geforce 920M. Its a pretty low end card and I wasn't planning on gaming on it, it was a rush buy and I've used it mostly for browsing honestly uptil now. Anyway I tried running a couple games and the problem I face is after around 2-3 mins (varies from game to game) it crashes. Sometimes I get a black screen, sometimes it just freezes. The laptop becomes completely unusable at the point. Forcing the games to run with the intel graphics solves the problem but I want to know how to fix it. It doesn't matter what game it is, I was playing Half Life and it crashed in 2 min whereas I could run like GTA V and Sims 4 for a good 30 minutes before it crashed. Any help is appreciated thanks.