If it's the controller that's failed rather than the drive you may be able to get the drive out of the case and connect it to your computer (or put it in a caddy) so that you can extract the missing files. I don't think the "please insert disc" necessarily means that it's the drive that's bad. Of course it may not be worth the risk (connecting inside the PC) or expense (caddy) for the files that you don't have copies of.