Cannot select the G-70 device
Was the driver installed correctly?

Have you installed several MIDI devices?
Windows XP/2000 place a limitation on the number of MIDI devices that can be installed. Even changes from one USB port to another count as “MIDI device installations”. If the limit is exceeded, you cannot use the device even though it may have been installed correctly. This is due to the limitations of the OS. It is not a driver problem.
You may be able to achieve normal operation by uninstalling