http://forum.xda-developers.com/show....php?t=2437992 to instal "bravia_experia" ,i had jailbreak and everything the instalation required.
basicly everything went well after instalation, i was able to reboot,power on/off as before.
yesterday i fell asleep with my phone playing music (battery around 55%),when i woke up it was powered off( i thought it was due fact that the battery couldn't last all the night playing music,as always) so i charged the phone for ~30 mins. when i tried to power it on it simply didn't do anything.
also ,when i charged it i used the usb port from the pc,and at every few minutes the pc played the same sound it plays when i plug the usb into the phone,at the same time the screen went on showing that battery's at 0% and then suddenly at 100%.
i charged the phone for 10 hrs ,tried to remove sim&sd card but still can't power it on.