ASUS G73JH w/ ASUS Monitor shuts down while gaming

I've had my G73JH Laptop since 2011. It's been a great laptop and it runs every game that I play well. Just recently, however, I purchased an ASUS VN247H-P monitor to go along with with. The monitor looks great and all works well unless I boot up a game. When I use the monitor my laptop is closed and positioned to allow proper venting from the back exhaust ports. After playing a game for 10-20 minutes the screen will go black and the laptop will shut off. Normally, when I reopen the laptop and turn it on it just says "Resuming Windows" and acts as if it wasn't forced into a full-on shutdown.

Now, this happens with most games I play but not all. I can play Hearthstone fine for hours but with other games I've been playing some of recently such as WoW and Dust: An Elysian Tail it does shut off.

I should also note that if I play these games without the monitor and just use my laptop screen that none of this happens. It works just fine.

Can anyone help me!? Thanks!

 

It sounds like overheating to me, and with different games it may or may not reach the thermal shutdown threshold.
Can you test again using the same procedures but without using the external monitor to see if the same symptom would re-occur?
Additionally, can you use AIDA64 ( AIDA64 | PC Benchmark | System Diagnostics | Stability Test .) and monitor the temperature while playing?
Since you've used the system since 2011, have you always kept the system clean such as heatsink/vent using compressed air?

 

I'll use AIDA64 and see if it overheats.

I've always tried keeping it clean but I haven't checked inside lately. With this laptop it's hard to get to the inside where any dust could accumulate. I'll see what I can do,

Thanks.

 

The G73 models were designed to intake air through the keyboard area, when you close the lid it blocks that causing it to overheat. You'll have to keep the lid open.

 

You can shut off the display if the light would be a distraction.