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.
Follow these steps to scan from the computer using the HP Scan software. Place the item to be scanned on the scanner glass or in the document feeder. On the Dock, click Applications, and then click Hewlett-Packard or your printer.