|Your information is very UNCLEAR.|
Do you have a laptop or a desktop computer?
The external DVDRW drive will NOT work properly with just one USB connection - one USB port by itself can't supply enough current.
If it has a Y cable with two USB connectors for the computer end, or two cables with a USB connector on one end of each for the computer end, you must connect both of them to the computer, or one of them to the computer, the other one (the one with two wires if applicable) to a 5v power adapter with a USB port, such as one for charging an MP3 player.
If it has a cable with one USB connector for the computer end, and an external power adapter that came with it, you must connect both the USB cable and the power adapter.
It may not work properly connected to a USB port or ports in a USB hub, or connected to the front USB ports on a desktop case - plug the USB connector(s) for the computer end into a USB port directly connected to the mboard.