Hello,
I have 2 users who are running Windows 7, and several network printers. On some mornings when they start the day, their printers will be missing entirely from the 'Device and Printers' menu, the menu doesn't say offline or anything, the printers are missing entirely until they reboot their computers. Other users in their department are not having any issue with losing the printers. The Event Viewer shows that the print spooler is terminating unexpectedly, but it does start up again by itself, and the print spooler doesn't crash in time with the printers going missing. For example, this week one of them lost their printers on Monday morning (3/3), but the event viewer shows that the last time the print spooler stopped, was on 2/28 in the morning. Their problems are also not in sync with each other, one may lose printers one day, and the other may lose them a few days later, sometime it doesn't happen for a few weeks at a time as well.
Stop you spooler (If it is running)
Remove the printers from the list,
Clear the spooler folder ("%WINDIR%\system32\spool\
Try to start the printer spooler,
Now try install the printers again
http://social.technet.microsoft.com/Forums/en-US/3339d135-ecbf-46d9-9e4f-d1ec187baaa8/windows-7-printers-have-disappeared-printer-spooler-wont-stay-running
Regards, Shiva