I would like to ask if what application on PC can i use to back up my data from z3? Please help me

[Samjc]

I actually want to back up my files. Then recover it at some other time. Which means all my data was there and also my mails and email. Hope someone will help me.

[Uliwooly]

@Samjc 

you could use Xperia companion, there are also other alternatives 

Xperia Companion (XC)

Software Repair Guide

Alternatives on How to backup Xperias

http://talk.sonymobile.com/thread/36355

As for the Emails, you shouldn't worry as they are stored server side, you should be more concerned about your photos, videos an music files