Thanks for the ideas/suggestions! Here's where I am now.
Figured out how to get out of the black screen. Two options work.
1. Reboot, then amend with "nomodeset." This gets me a nice centered, 640x480 display that cannot be expanded to 1024x768. It also goes away when I shut down and reboot - back to the black screen. However, I was able to access the xfconf file and reverse the changes I made earlier through Settings Editor. Not really sure if any of that was actually causing problems. Sometimes it boots to a black screen, sometimes it boots to a partial screen - 640x768 ... in upper left corner.
2.The second option is the reboot and select recovery which puts me exactly where I want to be ... 1024 display and the options to select 800 or 640 screen display. I think maybe recovery is booting me into a "live" version of the program??
I know this partial screen issue has been earlier identified with this model 1100 with the Intel 845 graphics. I found web search references with several "resolved" solutions - none of which worked for me.
update bios. Already current
update Intel microcode. Done - no efffect
i845.modeset=0 Done - no effect
xforcevesa Done - no effect
So ... how do I change this install to retain the boot setting which take effect when I boot through the recovery option??? That will fix this problem.
Please excuse my ignorance of commands/terminology. My understanding of Linux is basically limited to a personal opinion that I really like it, and would like to use it on this old machine!
Thanks again!