[help]sony ericsson w8 not responding after switching on

I updated my phone from ginger dx v27 to semc debrand engine v3.0 without unlocking boot loader and without updating kernel version...
now on startup,only sony erricson is written on the screen from more than 10 minutes.
i am pressing the back button again and again but nothing is happening...:crying:
please tell me what to do...i am afraid if my phone is bricked...
please help:(
please reply as soon as possible..