SPECS:

ASROCK Z87 PRO4 ATX LGA 1150,
INTEL CORE I5-4670K,
EVGA GTX660SC 2GB,
WD 1TB 3.5INT SATA 7200 BLK,
CRUCIAL 8GB 4X2 D3 1600 DIMM CL9,
INLANDPRO IL SILVER 600WATT ATX PSU

Currently Running Windows 8.1 with all drivers updated and checked

I am currently playing Final Fantasy 14 ARR and while the game runs smoothly at 59FPS no matter the settings and certain times my computer crashes. This happens in 2 ways. 1) The monitor goes black while flickering between analog and digital mode(its dvi connected) and the sound locks. After a second or two it comes back and everything is fine. 2) Screen lock up and shows a random color while the sound is stuck and the sytem hangs like that until i manually press the power button.

I thought my gtx 660sc was overheating so I downloaded an EVGA utility to adjust fan speeds, it usually runs 40-50c while gaming now.

I also though my cpu might be overheating so i bought Cooler Master HYPER T4 CPU COOLER instead of the basic one. Strangely my system still idles at 40+c.
I am running out of ideas i hope somebody can please help me diagnose and solve this problem. If this is not the right place id like guidance where to take this.
Thanks.