iPhone 4 suddenly stopped syncing with iTunes or charging and is not recognised by computer when plugged in via USB.

OS: Windows 7

Browser: IE 9

iTunes: version 11.01.12

iTunes has suddenly stopped syncing with iPhone 4 in the last week for some unknown reason. I plug it in and it doesn't register - doesn't charge, doesn't sync, and doesn't appear in computer devices.

I have not upgraded/altered anything on iPhone or computer

I have tried another USB port with a working device in it, still nothing,

Restarted iPhone,

Restarted computer,

Tried another cable,

Phone fully charged and otherwise functioning normally,

Still no luck.

Have googled this and wondering if it's the device drivers or the things that negotiate the connection through the USB port between phone and computer?

Wondering if there is anything else I can try or whether this requires a service.