After receiving many suggestions from members, I found a possible issue that was causing my crashing problem. To remind you, the crash would occur when attempting to save new text on a page, or after making text changes and attempting to preview the changes.

I noticed that the font list was not displaying in V12. This led me to look into other font programs I have installed on my computer. One, distributed by Summitsoft (related I believe to Incomedia) was causing the font conflict. After uninstalling the Summitsoft software, and reinstalling V12, the problem has not resurfaced. V12 is working great; I have several websites up and running, and customers and viewers are very happy with the results.

Thanks to everyone who made suggestions. I could not comment using the previous thread, so I added this message to express my gratitude.