The most direct way if it is a desktop is to buy a PCI card (if those
are the I/O slots you have) with two parallel ports. They are cheap.
I've used Syba from NewEgg -- just check tht it is VISTA compatible.
Otherwise a printer server with two ports would seem to be good and
available to other computers if you end up with more than one.
The DJ1220 only has the driver for VISTA that is "in the box" ie that
comes as part of VISTA. However you run the risk that it is not fully
featured to do all the printer is capable of doing.
Here's the document HP have on installing for it:
I have a LJ 2200d and it works fine; there is fully featured HP
software you can download for it.
You may need the PCL driver and the Easycare software to get everything
working -- I think the latter includes the HP Toolkit that is needed.
I no longer remember enough about PCL to know the difference between
PCL 5 and PCL 6. People who could tell you, I'm sure if noone here
chips in with the information, would be in:
I hope that helps.