I am installing the same caio lk220 keyboard in two machines, in one of them, the keyboard is installed using an Usb composite driver and a Usb audio device driver, and works ok. Trying the other machine the lk220 is installed using an Usb composite driver and a Casio Usb-driver but this last with the yellow mark, indicating that is not working. Could somebody explain what is happen and if a need the Usb audio device driver, where can i download it or if somebody can send it to me, thanks in advance