printers are lost .

Just a quesion that i had asked to me and wanted to see if i could get an answer.

There is a network issue where , no one can print and cannot see the printer shares at all.
The internet connection is fine and all users are able to retrieve files and use apps on the network .

I go in and reboot the server and now you can see everything , does anyone know what was the cause of the problem?

P.s. stand alone print server
Win 2000
Active directory