Xperia Z1 freezing

[NadaAbouElenien]

i was chatting on Whatsapp and suddly my xperia z1 freezed on the same screen .. dont want to shut down or restart or go back or do anythings... it still like that for hours

[_alexdon_]

Force shutdown:

http://userguide.sonymobile.com/referrer.php?region=global-en&product=xperia-z1#!Resetting-your-devi...

Turn it on.