I have a document stuck waiting to be printed or to be deleted and blocking up all future prints.
- stop the printer spool service: Control Panel > Administrative Tools > Services; right click on the Print Spooler service and choose Stop
- in Windows Explorer go here: C:\Windows\System32\spool\PRINTERS\ (note: the drive letter of your Windows folder may be different)
- delete all files within the PRINTERS folder
- go back to the Services window: right click on the Print Spooler service and choose Start
Note: this works even with network printers