Sony Xperia U not working after failed update I've been having problems for some time with my phone connecting to my pc/charger which Sony advised me to correct with the latest update. 

However, when I tried the update failed twice and now my phone just shows an error screen with an exclamation mark and phone.  

Can't do anything with it at all.

What can I do to fix it?
As it is a software issue, and you have not used a custom ROM, the best thing to do would be to send it to the Sony repair centre.