Screen goes black after a couple minutes of Gaming, Please help

Hi i got an Alienware m18x laptop about 2 years ago, it ran great for but about a month ago a problem occured where after 10-15 minutes of Gaming my computer would turn off (bugcheck 116). The only way i could fix it was by resetting my computer to factory settings. My computer worked fine for about a week then I was playing League of Legends and my screen just went black, it wasnt like before where it would reboot, my screen would just go black (my keyboard lights would still be on and so was my computer). Then you had to hold the power button to shut it off then start it up again and it would be fine, so I went back to my game and after 3 minutes it happened again. I reset my computer again to factory settings but it still happens, I clean my computer out every other week and all the fans are working.

RAM: 8.00 GB
Operating system: 64 bit
Windows 7 Home Premium
Processor: Intel® Core™ i7-3610QM CPU @ 2.30 GHz
Graphics Card: NVIDIA GeForce GTX 675M

If you need anything else from me don’t hesitate to ask.

Have you read this long thread?

They talk about both the m17x and m18x in that thread.

Doesnt look like your laptop is overheating