We have a desktop running Vista Ultimate on a workgroup. There are two primary printers--one share from another computer in the workgroup and one is a neworked document center. We have installed the Vista drivers for the printers. However. every three to four days when the user of this machine tries to print, the desktop says no printer installed and asks for printer to be installed--which he does and everything works fine for a few days then the problem recurs. Also, the problem sometimes occurs when he tries to send an e-mail from Outlook and before the e-mail can be sent the computer asks that a printer be installed. Any suggestions would be appreciated.