Success!!!!! It's working!

Manually inserting the IPs into the printer was a bit fiddly but not that bad, really. Had to watch out for two slightly-different sub-menus, one called "TCP/IP", at which you arrive first, and the other called "CFG TCP=YES/NO". Unless you're aware that both exist, you can select the wrong one and then wonder why you're not seeing a whole raft of additional menus.

When I went back into the printer's properties in WinXP, I'd already had the port set up to a Standard TCP/IP Port with this printer on it, from the previous unsuccessful attempts. Apart from entering the printer's IP address into the port's dialog, I therefore left it "as is". However, the resulting nomenclature in the Print dialog itself isn't brilliant now, as it's:

Type: HP Laserjet 4/4M Plus PS600
Where: HPLaserjet4MPLusPS600

So, in order to perhaps be able to make this better (for example, "Where" would be better as "192.168.0.10" or "Network"), will it be okay for me to delete the current Standard TCP/IP Port in the Properties dialog and then add a fresh one and reconfigure it?

Might be a case of "if it isn't broke, don't fix it"!

If it ain't broke, I'll break it
If it is broke, I'll break it some more

In reply to a post by meditator:

So, in order to perhaps be able to make this better (for example, "Where" would be better as "192.168.0.10" or "Network"), will it be okay for me to delete the current Standard TCP/IP Port in the Properties dialog and then add a fresh one and reconfigure it?

That's what I would do - you've done the hard bit, getting the printer configured..

Bear in mind you can also change the name of the *Printer* to better suit what you need.

I deleted the Port setting and invoked a fresh "Add Standard TCP/IP Printer Port" wizard. This time, I filled in the printer's IP address rather than its name and, underneath, changed the Port Name to "Network". I then changed nothing in Configure Port, back in the main Properties dialog. As a result, I now see some better namings for "Type" and "Where" when printing.

MAY I SAY A VERY BIG THANKYOU TO ALL OF YOU, for helping me get the appropriate addresses into the printer and for generally configuring it for the networked situation.

I'll be getting a Mac laptop shortly - a completely new venture for me, as hitherto I've been solely a Windows man - and so I hope that configuring the Mac for printing via this network will be as easy to do as in WinXP.

Glad you got it sorted in the end.

Mac's support LPR printing over IP so shouldn't be hard to accomplish now the printer is set up.

Just as an afterthought: I've noticed on the testpage printout I got from the printer that CFG NETWORK = NO. And yet I had set this to YES (and definitely pressing Enter after). Does anyone else get this? Or is it that, when you set it to YES, it stays in that state only for the current configuring session and then automatically flips back to NO?

It always says no to begin with. Setting to yes unlocks the submenus so you can set up IP, etc. Don't worry about it, as long as the test page shows the network details you set up, it'll be fine.

Thanks for that reassurance, shtu.