回复：求助！外接的DVD writer通过USB连到Computer上，

There are a few things you can check:
(1) External DVD power on?
(2) Plug in a flash drive to that USB to verify that USB works. If not, try different USB
(3) Check USB cable no problem
(4) If you are running XP or W2K, no driver is needed
(5) The only driver you will need for your external DVD is the application software which do the reading and writing job, such as Nero...