Can't Print to a Printer shared from Windows XP

I have just installed Windows 2000 on a client machine of mine that used to
run Windows 98.

I have 3 printers in my shop:

Canon Pixma (Shared via USB on a XP Comp)
Hewlett Packard 2200 (Shared via Network on a XP Comp)
and a Hewlett Packard 2420 (Shared via Parallel Port on a XP Comp).

Now I can install all 3 printers simply with no problems. I can print to the
Canon Pixma and HP2200 with no problems. But I cant print to the HP2420, the
Windows Test page printed fine but Nothing else will print. It is crucial
that I can get Windows2000 printing to the HP2420 Printer as it's our Main
printer and its unconvinient to print to the others.

Does anyone have a clue as to what may be going on? I've tried reinstalling
it and installing it 5 times now, but I have no luck printing.

I have to get this Sorted ASAP.

I'd appreciate any help! Thanks