If DLC stops working after installing HP print drivers, your registry entries for HP printers may be corrupt.
Other symptons are the Hewlett Packard Network Port option may not be listed in the Available Printer Ports box of the Add Printer Wizard and the Spooler may stop responding, leaving jobs in the Spool folder.
Use Regedt32 to navigate to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Print\Printers\<PrinterName>
Delete entries for your DLC printer(s).
Use Control Panel / Services / 3rd_Party_Service to Stop all 3rd party services.
Use Control Panel / Network to remove the DLC protocol.
Shutdown and restart your print server.
Reinstall the DLC protocol in Control Panel / Network.
Shutdown and restart your print server.
Reapply your latest Service Pack.
Shutdown and restart your print server.
Use the Add Printer Wizard to reinstall the HP Network Port.
Install the printer(s) that you deleted.
See tip 1206.
