Why cell phone screen not show when the power also on and mobile is in running position?

[AC Question]

my cell phone samsung s3 dispaly problem. when i press the power button , the blue light blink which is on the top left corner for just 1 second and no logo and nothing displayed on screen just still black screen . after that i press home button then back and menu button light blink and nothing show in screen .... what can i do that time..... i want to do reboot and all that but nothing can be happend when i press and hold power+home+vol up button....... plz help me.... my data is in it . pictures and all that what can i do for backup and how can the phone screen displays..........