Thanks for the reply Russ. They are the World Family Tree series. With Family Tree Maker running, I was able to pop them in the cd drive, and then choose "View > Data CD", scroll thru the surname index page to find if there was someone of interest, then double click the name (or click button) to view the person in a tree format. No data is actually transferred to my HD, or another CD, just viewing them with FTM. I suspect FTMaker *temporarily* loads the tree (or ged) from the CD disk. When finished looking at the tree with that person's info, I click the "back" button in FTM, which brings me back to the index page, to choose someone else to view.
As mentioned in my OP, all worked fine last week when I skimmed through the disks quickly. Now when I access the disks (in the same way) FTM will "hang" after checking out maybe 6 persons in/from the index on the cd's. When FTM "hangs" while viewing the disks, I've noticed it does so after clicking the person in the index, and doesn't make it to seeing the tree format for the person. Tonight I uninstalled FTM and re-installed in hopes it would solve the problem. I've checked all the settings in FTM. It worked OK for a short time, then the same problem.