So I finally got around to installing the printer (which involved Stella crawling around behind my desk and trying to sort out which cables belonged to the old one first).
Took me quite a while, though. The instructions in the little leaflet that came with the printer were all right, as far as they went: plug in printer, computer detects new device, install drivers, reboot. So far so good. Except that there weren't any new printers listed after the reboot.
So use the troubleshooting advice HP kindly included: remove USB cable and CD from drive, reboot while holding down Shift key, install driver from CD and don't connect USB cable until prompted.
The program certainly noticed when the USB cable was inserted since the "please insert cable" message went away, to be replaced with one saying "New printer recognised; please wait" and a greyed-out Cancel button. This dialog box stayed on screen for about twenty minutes until I lost patience and rebooted.
So, consult the "real" manual (which is pretty tidgy); it suggests to disable any antivirus software I may have installed. So I try again, this time shutting down my Personal Firewall (and most other programs as well) first. Shouldn't be a problem since I don't have an open Internet connection. Still no dice.
I wish there was somebody to phone, but no, phone support isn't available in Germany. So I start crawling around http://www.hp.com/support and find an "E-mail support" link, which I try. I enter all the things I've done and decide I'll probably get no answer before next week, what with the New Year coming up and all, but oh well.
A couple of hours later, though, an email comes in suggesting that when that window comes up, I go to the Device Manager, delete USB printing support, and click on refresh, which'll re-recognise USB printing, install the driver, and recognise the printer and complete the installation.
Sounds crazy, but what have I got to lose? And it worked. Bizarre.
Computer wouldn't shut down properly, but after rebooting anyway (with the associated CHKDSK), it shut down fine that time.
Now I get to decide whether I really want three or four HP processes hanging around my system all the time (one of them apparently is a scheduler for updates) with wonderfully descriptive names of HPZTSB08.EXE and HPOTDD01.EXE, and an extra icon in my system try which is pretty cluttered already.