What role does the print spooler service play in an HP printer's ability to print a test page, and how do I restart it?

The Print Spooler service is a critical Windows component that manages all print jobs. When you send a document (including a test page) to your HP printer, the Print Spooler temporarily stores it and then feeds it to the printer. If this service is stopped, crashed, or stuck, no print jobs can be processed, resulting in an 'error printing test page.' To restart it: press Win + R, type 'services.msc', find 'Print Spooler' in the list, right-click it, and select 'Restart.' Ensure its 'Startup type' is set to 'Automatic'.