Dell INSPIRON N5010 - OVERHEATING & SUDDEN SHUT DOWN ISSUE

MY DELL INSPIRON N5010 SUDDENLY SWITCHING OFF & FOUND HIGH TEMPERATURE AT THAT TIME.

WHEN I START IT GIVES ME 'START WINDOWS NORMALLY' & OTHER OPTIONS.

SPECIFICATION:

INTEL CORE i5 M480 2.67GHz (BOOST UP TO 2.97)

4GB DDR3-1066

1GB ATI MOBILITY READON HD 550V

help me