SD and BOAC,
Many thanks to both of you!
SD, re-installing the printer driver (an HP) didn't work, it still called for the Windows spooler itself.
My command line command was "echo hello ctrl-L dir > LPT1", so that would have written straight to the port and bypassed everything.
BOAC, thanks to your instructions I found the right spots in the wilderness, and they seemed to indicate that spoolsv.exe had indeed been corrupted.
Since I had doubts about the 'how' (hence about what elsee might have been corrupted at the same time), I just went the whole hog, and re-installed XP.
That did the trick.
Cheers!
CJ