Turning the power ON/OFF while the print monitor screen is displayed may cause the printer driver to go off-line and make printing impossible.
 

In this case, open the [Printers / Printers and Faxes / Devices and Printers] folder on the computer and check if your printer driver is shown as off-line.
 

If it is off-line, close the print monitor screen and turn your printer power ON/OFF a few times. If this procedure is unable to make the printer driver go on-line, restart the computer.