Alienware m17x totally without power

I own an alienware m17x r4, my son was playing borderlands 2 when the computer totally died and is total without power, the supply is fine and lights up and also tried a second supply, the laptop is about 3 years and 300 days old, surely this should not have failed as I would expect a longer life span than this for a premium laptop, where do i stand on a repair?

I know in the UK we have the 6 year rule on expensive items, does this fit into that category (hopefully).

This was the laptop that I have always wanted but could not afford till now because it was second hand but boxed and perfect, it is as came out of the factory.

PLEASE HELP ME SOMEONE!!