What to do if xperia Edual turn on and off automatically

[janeEst]

What I have to do if experia Edual on and off automatically 
I want to master reset in my phone but the phone turn off by itself
I turn on the phone back and it off in less than 2 minutes..I don have the chance to master reset it
and I've install the flashtool for experia (Emma)
and I already done the step to connect the USB to the phone but the Emma could not read my phone....
What should I do???
Please help me..I don know else what to do....

[Alexander1]

You could try to start your phone in safe mode. Maybe it will prevent the phone from restarting: 

http://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/m-p/348008#U348008

Also you could try to repair the phone software using PC Companion: 

http://www.sonymobile.com/update

In PC Companion, press start on Support Zone > Start on Update the phones software > Press the blue link that says "Repair phone"