xperia z3 shuts down and up without any reason

[mista_bubu]

my xperia z3 shuts down after using it for 2 or 3 minutes, then it starts to restart, without any pressing on the power button. it becomes very warm after 10 minutes. i can just break through the circle Holding the power button and the 'louder' button for a few seconds, until it vibrates 3 times. in the morning it worked normally, middays the problem was there.. what can i do?

[Thommo]

Remove your Sim and SD cards and check to see if the same occurs as this is normally associated with faulty cards

[mista_bubu]

removed sim and SD card, started the device, but its still the same Problem. the screen freezes for 2 sec and it shuts down and it restarts again. but im thankful for answering, thx

[Thommo]

Your last option is to try performing a system repair using PC Companion as this will often fix issues - This will factory reset your phone and erase all data so best to backup before you begin

Switch off your phone and unplug from Pc (Hold volume up and power for around 10 seconds)
Start PC Companion and select Support zone then Update my phone/tablet then in Blue Repair my phone/tablet and follow the on screen instructions - When prompted connect your phone still switched off holding volume down or back button - This should start the repair or reformat process

If you are using Windows 8/8.1 or a 64bit operating system then adjust the settings for PC Companion and run in compatibility mode and chose Windows 7 or XP

[Thommo]

If that fails then I'm sorry to hear this but you would need to either return your device to the place of purchase or contact Xperia care and have your device inspected http://www.sonymobile.com/global-en/support/contact-us/

[mista_bubu]

i will try it as soon as i am back at home. im very thankful for your help. thx