Question PC suddenly shut down, will not boot up

May 14, 2020
This is my first time posting for help for a PC issue as I can usually diagnose and fix it myself.

My PC suddenly switched off last night whilst I was playing a game. I attempted to boot it back up again but with no success. The PC appears to turn on and the power button is lit up, my connected USB devices are powered up but no display and the CPU and MB fans aren't spinning. I'm not sure about the gfx card fan as it's behind a cage.

My specs are: Alienware x51 r3 (with whatever stock MB it uses.) 2 x 8GB 2666mhz DDR4 RAM (clocked to 2500mhz.) NVIDIA Geforce GTX 970 250GB Samsung EVO SSD 2TB FireCuda Hybrid HDD 500GB HDD I have a KB and mouse connected via a USB dongle, and 3 external drives.

I suspect a power issue or a fried MB but I can't test it as the power supply is a proprietary external brick as opposed to an ATX..

The BIOS locks overclocking on the CPU but I do sometimes OC my gfx card a little.

I was hoping someone here could help give me a little insight as to where the issue might be and whether or not any components are salvageable. Thanks in advance.