First download and install the latest driver for the USB Music Pack here..

Note: The USB Music Pack interface will only work under Windows 2000 and XP. It will not install or work properly under Windows Vista. If you have Windows Vista and need a compatible interface, please look into the Edirol UM Series MIDI interfaces, which are Vista compatible.

Once you have download the USB_Music_Pack_Driver.zip file, double click to open it, then open the Readme_E.htm file which will have detailed instructions for installing the driver properly.