Alienware 17 Laptop Screen not Working

Hi.

I bought a Alienware laptop from eBay a few months ago.

I was working perfectly until now.

Yesterday i left my laptop on my desk and went away from keyboard for about 5minutes, and came back to see my screen was blank. Since it was late at night I didnt bother doing anything and just manually turned it off by pressing the off button.

Today i turned my laptop on again but the screen does not show anything.

I cant see the boot logo or anything else. But when i connect it to my TV using HDMI i can see my login screen meaning the laptop is on and working.

The laptop is still under warranty till March 2015, but I would like to know if Dell will still repair it, since some people I asked said you need to transfer warranty etc. 

Also if there is any fixes i can try please let me know.

Also the backlight is on. Just the screen is black/blank

Thanks