Sony xperia soft bricked ??

Turn off the phone, and unplug it from the PC !
- On your PC, uninstall Sony PC Companion
- Restart your PC
- On your PC, clean any Cache and Registry related to Sony PC Companion, then restart PC again.
- Reinstall Sony PC Companion by downloading it from here

- Turn on Sony PC Companion on your PC
- In Sony PC Companion, enter the Support Zone tab
- Go to Update Phone Software

A window will pop out, saying that it cannot find your phone

- Click on Fix Phone
- Click on Continue

A window will pop out, saying that you will lose all your data

- TICK the BOX
- Click on continue

An update process will began.
Wait for it to show a window with all the SONY mobile phones

- Find your phone 
- Click on the phone.

Now all you have to do is follow the on-screen instructions. It will tell you to hold some button and connect to the PC, then it will erase everything, and download the original ROM to your phone

It may not work at first time jus uninstall pc companion and repeat the steps.