[Nabeshein]

Best place to start if you have no idea sounds kinda harsh, but has never failed me. Back up your stuff to your storage card and hard reset. If you've already done that and it didn't work, I'd say get a hold of device insurance if you got it, your usb port may have taken a poo (I've got a Diamond, and it happens a lot on that model, could happen to yours too).

But, definately, hard reset first.