I have downloaded a printer driver for HP Deskjet 320 onto a floppy to install on my Packard Bell AX 255CD which is not on line. Do I have to uninstall the other printer drivers currently on the PB before installing this new driver?

you can but dont have to the drivers will install next to the existing drivers, but keep the system clean while you are in there remove the old printer then run the hewlett drivers

Well it depends, Do you plan on using your first printer ever again? If the answer is no, then I would remove the first set of drivers, so you will not lose any storage space when adding the second drivers, but If you do plan on using the first printer again sometime in the future, then I'd leave the orginal drivers on. Now, if you use both printers a lot you can buy a devise that will allow you to switch between two printers buy way of your keyboard, and if you don't use the devise then you will need to switch printer cables at the printer, and make sure that in your printer set-up it is set to operate that printer you want to use. When changing printer cables between printers always make sure that power is off on the printers, and the computer.