Monitor Turns off..Cpu still Running and the num lock and other keys are responsive and no sound

Vz97

Reputable
Dec 13, 2015
16
0
4,510
Hi...
My PC runs fine for 10-15mins of gaming..then after that the monitor says "Cable not connected" but the CPU is still running...GPU fans are still running and I can toggle the num lock on and off(the green light goes on and off)..
but there seems to be no response on pressing the keys and there is no sound coming after the monitor shuts down..
I managed to check some posts all of them states that maybe there is a problem with the GPU or RAM or HDD..
Please Help me to identify what the exact cause is..
Thanks in ADVANCE

PS: I got an error while booting up today(5th Dec) ...It said "Please Power Down and Connect PCIe Power Cable(s) for This Graphics Card "

My Specs:
CPU: FX6300
GPU: GTX 960 OC edition
RAM: Corsair Vengeance 8Gb stick 1600mhz + 2gb of transcend 1300mhz
PSU: Corsair VS450
 

Vz97

Reputable
Dec 13, 2015
16
0
4,510
Update: Now I Opened the Cabinet to check for any loose wires and I plugged out the 6-pin PCIe connector from my GPU and the PC won't turn on now..
Tried With another GPU the PC works fine..But when I reinsert my GTX960 the PC won't boot