Forcefully Clear the Print Queue in Windows Servers

Go to Start, Control Panel and Administrative Tools. Double click on Services icon.



Scroll down to the Print Spooler service and right click on it and select Stop. In order to do this, you need to be logged in as Administrator. 
(NOTE: No one is able to print once the service is stopped)

Browse to C:\Windows\System32\spool\PRINTERS
There are two corresponding files for each print job, a .SPL file and a .SHD file. Delete both files

start the print spooler back up by right-clicking on it and selecting “Start.

Refresh the window on the print queue and it should now be gone!