i am flash my xperia mini pro sk17i for jb but then it can't turn on

[M-]

when i am flash my phone for jb 4.3.x then it never start please give me some idea for  turn on my phone

and my phone shows only back butten light for some time and off after some time agian shows back light and off

[M-]

please help me for my dead device xperia mini pro for above post please help me........