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.
Click the Windows icon, click All Programs, click the HP folder, click the name of your printer, and then click HP Scan. Select a scan option for the item you are scanning, such as PDF for a document or JPEG for a photo.