Alienware 17 (2014) Shutting down while gaming

My system has been shutting down whenever I game. I thought I may have been overheating, and even redid my paste on cpu/gpu and monitored temps with HWiNFO while gaming. But temps show nothing out of the ordinary. 

This started after a long session of BF1, when my system shutdown while gaming, and it was pretty hot at the time. Thats why I went and redid my paste. However, it now does it even when I barely use my gpu.

I am of the mind it may be the battery, as after it shuts down I can not boot right away. Lights will flash, but then nothing. I have to let it sit for a minute or two before it powers back on, and it will NOT power on without the power cable plugged in.

Just want to know if I may be missing something that I have not tried, I will order a new battery when I get the chance and see if that works.

Running fresh windows 10, everything updated as far as I can tell. 

I have run every diagnostic test I can find on the dell website, and all test pass.

sfc /scan also passed