In simple terms, it seems like your hard disk might be physically disconnected or has failed. But we would really need to know more about your system in order to properly help you. Is this a new or old system? Have you or someone you know changed anything on this system recently? Changed hardware, changed software? What is the system make and model?
A disk read error could be because the hard drive is failing. I would suggest you run chkdsk against your hard drive to see if that is true. If it is then get a new hard drive very soon and backup all your important data.