MY mobile not turing on?

I 'm using a sony ericsson w595 phone for d past 1 yrs.. today sharply 2:30 automatically my phone turned off and when i turned it on, it didnt turn on.. instead der was a vibration which usually comes while turning on, then a white light in the screen and back light was seen for 5 seconds and then it completely went dead!!! plz someone help me