Phone Screen black

[sh]

I was purchase Xperia u (ST25i) last year 30/06/2012. Before one month we face problem when I insert SIM card phone screen blank what types of problem this ??????????????

Sony 

Sony Support Centre no always switch off

[Alexander1]

Have you tried with different SIM cards? 

If the problem persists with another SIM card I suggest that you try to repair the phone software using PC Companion: 

http://www.sonymobile.com/update

If the problem should remain after a software repair I would recommend that you have the phone examined by a service center. For more information please contact your local support: 

http://www.sonymobile.com/update