If the computer displays the message that the hardware is not connected then you should check for two things: drivers and cable connection. Make sure the USB driver is connected to the computer and the device is turned on. It's possible that the cable is faulty and needs replacement. You can get one from Amazon, Ebay or your local IT shop. Alternatively, the drivers can be downloaded from the HP Support website. Choose your corresponding OS and then download the setup package which contains the driver and the software needed to scan, print, etc.
Make sure to run the application as Administrator because it will need system resources.