Napho, J.S., and db, thanks for your advice. It seems I've got the problem licked, with WinMx working well. (Yes, one has to have patience to cope with the queues, but the downloads are waaaay faster than KazaLite, or others of it's ilk).
The re-downloading of the .exe file helped, as I mentioned previously. then this morning I followed J.S.'s advice and got me a little (freebie) monitoring prog. which DietKazaa promptly threw into fits - memory usage went briefly off the scale! Next I disabled KaZaa, disabled ZoneAlarm, and WinMx worked perfectly from then on - memory usage down to 42%, and cpu similar.
And yes, db, welcome aboard - I'm sure you'll be happy amongst this band of most congenial people.