Iphone 4S stuck at Apple logo

Hi,

My iphone 4S stuck with the Apple logo screen. when i was in skype call suddenly my screen went black and phone got restarted, after that it was stuck with the apple logo screen and i am not able to switch off the mobile. after the battery drain mobile got switched off and I kept for charging but no use again same thing with logo screen. i tried may things like pressing home button along with power button for long time and i tried to restore my mobile with itunes nothing worked.

please sugget me some solution.

Regards,

Anil