When trying to add a printer you receive error message:
"Operation could not be completed. The Print Spooler service is not running"
in the list find Print Spooler service, check for Startup Type (should be automatic) right click and choose Start.
If the service starts successfully you can try adding printer again.
If after a short time you receive error message similar to this:
"Spooler subsystem app has encountered a problem and needs to close."
Download FixPrintSpooler.msi from Microsoft, run it and follow the instructions.
More info here: http://support.microsoft.com/kb/324757