Phone wont start

[sudmun]

I start my phone then when the home screen comes it stays in the home screen for 2 seconds then it shuts off again ...I can't open anything help!!!

[_alexdon_]

Force restart(power button+vol up until the phone vibrates).

[tonima]

this doesn't work! i tried but my phone only shows "sony' then again turned off.

[Fahim715]

Reinstall using PC Companion or SUS

[sudmun]

this doesnt work it shuts down again......and i cant even repair it with pc companion because it doesnt stay turned on for too long

[jackxperiaP]

no prob bro ..

follow this 

http://www.flashtool.net/download.html download flashtool ..

https://mega.co.nz/#!ngwBARRJ!H_XrsU5RH9iGN-iH3COmRlXf2xImsSnXy7DpJ4wYT3A this is our stock jb rom .100 

now install flashtool, then go to drivers folder in c/program files/flashtool/drivers and install driver for xperia p .. 

now copy the downloaded ftf file to the folder named "firmwares" in c/program files/ flashtool/ firmware

now click on flash button in the tool aft few min it ll ask you to connect your device in flashmode and u need to choose flashmode when asked .. now off your mob by pressing power button and vol key button untill you feel three vibrations .. now wait for two min and then press vol down key then connect the usb cable , now the flashtool begins to flash .. simple and easy .. if your device is not recognized .. again switch off and wait for few min before connection then sure it ll get detected ..

[sudmun]

still the same problem i flashed it the way u said it and it still shuts down like before

[sudmun]

Okay now it starts but does bot recognizes my SIM card....and my phone only turns on when there is no SIM card in the slot..... But if there is a SIM card then it shuts off like before...,.., I tried the SIM card on another phone and it worked fine