Weird USB connection problem - any ideas?

Hello all. I've got a problem with my N4 in that when I connect it to a PC via USB, the PC does not recognize any connection at all. It's not even saying "unknown device", just nothing. I've tried connecting it to multiple PC's (win 7, Win 8, Win 10) and with multiple USB cables, but I don't get anything. The only time I get something at all is if I turn on USB debugging on the N4. In this case, the PC recognised that a device has been connected, but doesn't seem to know what it is as it can't find the correct drivers to install.

This used to work fine on my Win7 machine, so I'm not sure what's changed. Anyone got any ideas what I can try to fix it?

Thanks for any help.