I'm just wondering if you're having the same problem that I had with my Xperia S.
It lost its ability to connect to anything via the USB lead. I could still charge it, but I couldn't connect it to my laptop etc, as it wasn't recognised.
The way round it is to install an app called "Airdroid".
Install the app on your phone and then on your laptop go to
http://web.airdroid.com/.
You can then transfer contents of your phone to the laptop over the internet - no need for a USB lead.