Z3C apps randomly stop working, phone restarts by itself

[tokays]

Hi, 

I'm having quite some trouble with my Xperia Compact Z3 (D5803). 

- It restarts by itself (not touching anything, it's next to me and suddenly I see it's restarting)
- About all apps freeze and display "this app has stopped working" message (google apps, sony apps... about everything) at some point, when I use the phone.

- I did a reset (from the phone) and hard reset (with PC companion), with no result : in fact, after the reset with PC companion, first thing shown is a message saying that hangouts has stopped working

- It all started quite suddenly, there was no change or damage on the phone that could have provoked this.

 Any ideas ? 

[_alexdon_]

Usually,it is recommended that you use proper nano SIM or microSIM and not cut your older one.