Lenovo a850+ hardbrick/dead android cause custom rom

Hi all member XDA..

I have problem with my phone Lenovo A850+
i try cusrom rom my phone with MIUI 7,with cwm recovery..
after all done with clear data then cache and dalvic, i install the miui7 rom from sd card , after done install the miui7 rom.. i reboot my phone.. so the problem is come.. my phone just on in black light(like blank phone) or stuck in black screen.
I already research the solution to fix my phone.. but im confused.. i hope somebody in XDA can help me to recomment or show the step to fix this problem..

Thanks for helping :)
GOD BLESS YOU