I reread your first post and got to thinking, that have you considered that this might also be a connector problem, because I think that the PC should recognize the device correctly regardless of the charge state. And the fact that the phone mistook the charger for PC, it could mean that the connection in the either part of the usb interface could be damaged. If it is the charger or the usb cable you are using, then you're lucky, but if its the phone then there arent many options left. There is long thread here about the usb-connector coming loose from the phone. You could try to charge/connect to pc using different cable and see if it works. You could also checkt that there isn't any foreign material or dirt in the phone side of the connection. Broken connector on the other hand would not neccessarily explain the fail-safe charging to the boot point and then nothing.