Printers not showing up in Windows 7
Sometimes a file gets stuck in the print spooler and crashes the spooler app. To fix it make sure the spooler is stopped, which it probably is. You can check with services.msc.
Then go to \windows\system32\spool\printers\ and delete all the files. Restart the print spooler after that.
The following command script should work:
rem net stop spooler
net start spooler