Load the HP Photosmart with paper and print a test page directly from the printer. On most models a test page can be printed by holding the "Power" button down for 5-10 seconds.
Verify that the test page prints properly. If the test page prints fine but sending a print job from the PC produces no output, the printer spool has probably stopped.
Log on to your computer and click on the "Start" button. Choose "Control Panel" from the menu.
Double-click on "Administrative Tools" on a Windows XP system. For Windows Vista and Windows 7, click first on "System and Maintenance" and then on "Administrative Tools." Double-click on the "Services" icon.
Right-click on the "Print spooler" service and choose "Start" to restart the print spooler. Right-click on the service again and choose "Properties" from the menu.
Click the drop-down button next to "Startup type" and change the setting to "Automatic." This will force the print spooler for your HP Photosmart printer to start each time your computer boots up.