Really Useful Windows Stuff 
Window XP
 
Windows Vista
 
Printer
To Clear stuck documents that won't print.
You have to stop and restart the print spooler.

Click Start and in the search box at the bottom, type cmd
Right-click on the command cmd.exe, at the top of the list and choose "run as Administrator". 
You may have to allow it to run, and a command prompt box will open.
In this box, type:
net stop spooler [enter] When if finishes and says the spooler is stopped, type in the box:
net start spooler [enter] Wait for it to finish starting the spooler. Now close the command prompt box and the printer may print the last thing you tried.