Phone just went dead for no reason

I was watching some tv and wanted to check the clock on the phone.. No problems turned it off again .. Then 5 mins later i wanted to check facebook but this time nothing happened when i pressed the power button. I tried holding it down for 10 seconds.. Nothing.. Holding down volume down + power button for 10 secs.. Still nothing.. Then i plugged in the charger which also gave me nothing at all, not even LED's lid up! Plugging the device into my computer yields nothing either not even a "USB device attached" sound from the pc..

Is there anything i can do i did the phone just kill it self? I would also like to point out that the battery was around 50% when this happened..