[Q] Help !! My SGN wont Turn on !!!

Hello everyone :)

My phone isnt working turning on , its stuck on the samsung logo !

I was using Ultimate jb rom when suddenly my phone turned off and it was stuck on the samsung logo , i tired flashing the another rom Angry v3 4.1.2 at first it the phone turned on and then the same happened , after that i tired flashing to stock ICS and now its again stuck on the samsung logo , what should i do now ? Please help asap :(

Thanks in advance :)