How to Change an HP Printer from Offline to Online

Turn on the computer to which the HP printer is connected. The printer does not have to be turned on in order to switch it from offline to online.
Click once on the Start menu.
Click 'Devices and Printers.'
Click the icon for the HP printer you wish to use. Where the status shows 'Offline,' click the word 'Offline' and then click the 'Printer' option on the pop-up window that results. Uncheck the 'Use Printer Offline' option.