still the same

I wanted to know if any body had this problem with there sp-808. I have a problem when I start my 808 it lights up but after the load up it say's (please insert zip disk) on the screen but when I insert the disk nothing happens. but the only button that works is the shift and thats it man I really would like to use this beat machine if anyone can help me that would be the best of help and thanks a big one =-)