It's possible that your phone has suffered the same fate that mine did.
The laptop didn't recognise it (although it used to do), but it would still charge. I took my phone to the repair shop and he advised me that the USB connectivity software had malfunctioned (or something similar to that) and it could be repaired for a small fee.
He did, however, explain that there is a way to transfer files from your phone to your laptop without a cable and without the need for a USB cable or bluetooth.
Download an app called "Airdroid" to your phone and open up the following website on your laptop:
http://web.airdroid.com/
If you want to create an account, it's totally free, or you can just scan the QR code with your phone, although I could never get that to work, so I just created an account.
Nothing is stored on the airdroid site, everything is transferred via the internet from your phone to the laptop. When you disconnect from airdroid, nothing is left behind or stored on the airdroid site, so there's no chance of anyone accessing your files.