How can I fix a sumvision 2.5 external box model Jx - 250U?

I bought the above external storage a few months ago. It has stopped working. It does not show up on any computers. I
They will only register that there is a device plugged into the USB port and gives me the option to close it.....but sad;y nothing else.

can it be fixed? All my music is on it, will I be able to retrieve it? Can you help me.

J
November 2007