9110 dead

Hi.
Today I tried to repair nokia 9110 with internal error. I dissambled and after that removed bat and did format with ctrl+shift+f. After It works fine,but I again dissambled for clean pcb. But after that computer section can't power on again,but phone section works fine. How I diagnose what is the problemm? Hardware or software? Is software is bad then it became dead? I already checked swith like glass diode with working fine. Give me all hints.
Sorry for multiply post. Becuase I can't distingwish this hardware or software.