Coombs' test involves taking a blood sample which is checked for the presence of antibodies which may destroy red blood cells.
You can use the HP Print and Scan Doctor to test the status of the printer spooler, print queue, device manager, and device conflicts. 1  On the desktop, double-click the HP Print and Scan Doctor icon to open the tool. 2  Click Start on the Welcome screen. 3  Select your printer, and then click Next.  Click Fix Printing.
Switch on the printer. For network printers installed on Windows Operating System computers, open the HP software. Click on the scanner actions, select manage, scan to computer, and then click on enable. Scan the document from the scanner glass or the automatic document feeder tray.