If you have no other drives connected to the system, it is possible that the internal hard drive has failed and will need to be replaced. This is one of the most common methods of computer failure I see nowadays. Do you happen to have model number of the laptop? If you do, we may be able to find a guide we can provide to help you open it to try re-seating the connection and if that doesn’t help, replace it. You should know that after you install a new drive you will need to re-install Windows and to make the installer flash drive you will need access to another computer.