I would look in the Event Viewer for clues.
I received a complaint from a user that he could not print (small-office, SBS2003SPI Premium, 10 clients). His PC and other clients are wireless, Win2K all patches. The printer he uses is physically connected to another client in the same sub-office. All network printers are shared and visible in the network directory, but I cannot connect to any network printer with any User account on this PC. When I try to access printer Properties (as SBS User) to print a test page I am given the warning:
"explorer.exe has generated errors and will be closed by Windows"
Logged in to the same PC as SBS Administrator, all printers work. I changed User's Permissions in Server Management to Net Admin and the printer works, no error messages. Ran SFC /SCANNOW and it completed fine.
The printer was working, so I am guessing the user of PC fiddled with some system settings affecting all users. I do NOT want him running as Net Admin!!! Any ideas?