What should I do if I cannot print from my computer on the HP DeskJet GT 5810?

First, make sure the power cord and USB cable connections are secure and the printer is powered on — the Power button should be lit. You should also verify the printer is set as the default printing device in your computer's settings. If using a USB cable and still unable to print, remove the CD, disconnect the USB cable, restart the computer, then reinstall the software without connecting the USB cable until prompted.