Before reinstalling from scratch and losing (or having to back up) all my programs and data, I tried to install Windows and drivers etc. on another hard drive first.
So I bought a 40 gig hard drive from eBay and played around -- without success, however.
Installing Windows would work fine (except for the very first time, where it didn't recognise the (wireless) keyboard any more once it had switched to booting from the hard drive, and so I couldn't enter my name and organisation, yet it wouldn't let me proceed without doing so), but then I couldn't access WLAN or the built-in TV tuner. Basically, those drivers on my driver CD that had setup programs seemed to work, but there were a couple that just had .sys and .dll and .inf files in the directory. Right-clicking the .inf file gave an option to "Install", but nothing appeared to happen.
So I thought, well, there are those strangely-named files in the "E:\Recover" directory; let's see whether we can use those. Apparently, they belong to a bundled version of PowerQuest Partition Image (or something like that) that will only run from booting the Tools and Drivers CD, not standalone. So I tried restoring the complete image; it warned twice that I'd lose all my data, but well, there wasn't any of my data on the new hard disk yet, so I told it to go ahead.
It stopped, whining about insufficient space. So I deleted the two partitions which contained the factory contents of D: and E: from the original hard drive (but were only about as big as I thought they needed to be to contain the data I did), and made one big partition. Still no dice. Perhaps some step decides it wants a drive as big as the one that's "supposed" to be in the machine, even if the data contained on the partition takes up less space.
Anyway, one last attempt went through the "install drivers only" option. That seemed to go all right, churning out driver after driver for about half an hour. The next time I looked, though, the system had restarted and appeared to be stuck on the Loading Windows screen (not the logo-on-black one but the later, logo-on-blue one).
I decided to give it some time, since the first step had taken quite a while, too, but after half an hour I "pulled the plug" and restarted. Loading went very quickly, but as soon as it got to the blue background, it stayed stuck in the same place.
My options, as I saw them, were basically to try to get the WLAN driver installed through phoning the hotline and asking for help, or to give the "restore back to factory layout" thingy another try with a sufficiently-large hard drive. I decided to go with the latter. I found a hard drive that looked as if it might even be exactly the same one as the one I had now (same manufacturer, same capacity, but slightly different name, differing in numbers after a decimal point, perhaps a minor firmware upgrade or something), which was even about 15 euros cheaper than most comparable-capacity hard drives, and order that. Along with some Cat5 cabling in case I can get connected to our Internet router via Ethernet, at least, even if I can't get WLAN to work. After all, the OS on the original hard drive will boot, though only through Last Known Good.