To quote UHF after the shop teacher cut off his own thumb... "Boy, is my face red..."
I installed it... It must have been my audio drivers that were preventing it from installing. I thought the Realtek driver installer was freezing near the end of the installation process, but actually it was taking more time than usual in either installing the new drivers or deleting the old ones. I updated those and SP1 installed fine!
(and for your assistance John, I will let your Paladin live... this time!
though he may get waylaid by a sneaky trap before the battle...
)