phone stopped working suddenly and went black

Yesterday i spoke for almost half an hour in the evening. Kept my phone side and working on my laptop after some time noticed that my phone was switched off. Tried to switch on , no use. then removed battery and reset it . Again tried to switch on , still no use. Then kept the phone for charging till today morning and tried switching on , still no use.

Plz help me.

regards

Sanjay