I recently connected a HP PSC 2355 all-in-one device to my desctop pc, then running Mandriva 2005le.
I connected the PSC 2355 and then went to MCC->Peripherals->Printers.
The printer was detected automatically and all software, including scanning software (Kooka),
was installed automatically. There is even a "hp printer Toolbox" program in Start-System-Observation.
The only part i installed manually is OCRAD (Optical Character Recognition).
For scanning i now use XSane.
Did you try installing/re-installing printer/scanner in MCC?
Regards,
Luc