Restart Print Spooler
1. Click on the Start button> Run and type 'services.msc'
2. Look Printer Spooler and check that the state is 'Running'.
3. If it is not running, right click on it and then select 'Start'
If the above solved you problem and the printers re-appears, then that is it.
If the printers went missing again after you tried to start a print job, then check if the Print Spooler is stopped again. If it is it, then do the next step
1. Click Start > Run and type explorer.exe
2. Go to C:\Windows\System32\spool\PRINTERS folder and delete all the files within
The above should solve the problem