Thanks for the reponse. I'm on Windows XP, but I set myself as the Administrator - no effect. The previous version is uninstalled. The Repair Acrobat Installation did not work. The program appears to crash each time you try to use a drop down menu. (I am old fashioned - I expect to buy something that works)
If you have a previous version of Acrobat installed, it must be removed.
You could also run the Repair Acrobat Installation from the Help menu.
My favorite quote - "Success is the ability to go from one failure to another with no loss of enthusiasm.