Unhappy Xperia v boot problem

Hi, i have xperia V (protoype). It was working fine, until i decide to put new Android (i was 4.0.4 on it). I don't have much of experience in flashing, but i did success already with my two other phones (ARC and P ), so i thought this time will be easy as usually. but...
phone was dead as stone..i spend more than week to trying all methods what i was able to find. now it's a big mess in my head and my PC, but now i made phone to start in recovery menu. thats all. tried install different roms, cyanomodgens-nothing... it just shows me SONY-->cyanomodgen and freez. at the moment flashtool can't see my phone.
if anyone can help me what to do( step by step), how to make this phone working again -i will be very happy person.
sorry for english.