Itunes and computer don't recognise ipod

I plugged my ipod nano into a set of speakers through the headphone plugin the other day and it completely froze. So, I reset my Ipod which also happened to clear all my music from it. When I went to plug it into my laptop in order to put the songs back on from itunes, my ipod was completely unrecognised. When I go into 'my computer', the USB which I plugged my ipod into doesn't appear and my itunes doesn't recognise it at all! I've tried putting it in disc mode, but after that, I'm unsure what else to do? PLEASE can somebody help!