Schrullenhaft, THANKS!!!
I finally got it working. I think there were two possible things that I might have done wrong:
First, it offers me two drivers when I pick the .inf file from the install directory: just the SiS 741, and another that supports several SiS models.
I think before I might have chosen the wrong one before switching to the plain SiS 741 version?? Maybe picking the other version first might have installed some portion of the utilities.
Second, maybe the AGP driver was not after all correctly installed. I updated it again this time too.
The long and short of it is, this time not only did I not get the SiS tabs in the display panel, which were not there before after the first couple tries, but I also did not get the SiS driver listed in the Add/Remove Programs. Before, even though I no longer had the SiS display properties tabs, I could still see it in Add/Remove Programs.
Now it's all fixed, and I owe you a beer. It will be convenient to play on my desktop again sometimes
So, anyone reading this, SiS 741 does seem to actually work ok if you get the procedure right to install the AGP and display drivers.