Based on the replies, I did some more checking.
The problem is something unique to one file.
The camera views work on other files.
I have searched the knowledge base, but have not identified a way I may have inadvertently turned the cameras off, or why I get blank pages.
Because the views work on other files, it is not a video card problem.
I have tried moving the file to a different computer and get the same resuilts, this pretty much eliminates a "computer problem" and highlights a "file" problem.
I can try creating a new file, but I would like to know how to fix this so if I do whaterver I did again, I do not have to start over.