Are you using the CS ODBC IO Printing Service? If so, you might try stopping and restarting this service and the print spooler service. If not using CS ODBC printing, then restart the print spooler service and see if that helps. If re-starting the server previously resolved the issue then it seems it could be one of the services stopping.
Also, you should determine if the printers are defined on the server and shared by the users. If so, you should test setting up the printer on a workstation and printing to the workstation printer from Sage 100. If that is successful then you have narrowed the issue to the server.