Thanks for the quick reply.
Yes, I *did* have a problem downloading, and it was only with the SP1.
(Never had issues with WU or any other downloads, or with wireless network to HSI (cable) router or bandwidth.)
It was 08:00 AM local time here in US, and I suspect the first failed download may have been due to high server load. It was downhill from there. Never even got to the installation step.
I knew better than to keep trying and canceling, but...
Anyway, the reset/reregister bat worked like a charm and didn't wipe out my WU history.
Plan to take a break for a while before tackling the 64-bit desktop.
Perhaps it will proceed a bit more smoothly!