After a download of Reader 9 my installer does not allow any additional programs to be installed. I receive the message that the installer is previously occupied. When I try to uninstal Reader 9 I get the same message.
In addition, there is a permanent little window that I can't close. It says "DocumentViewer" in the blue bar and reads, "An installation package for the product DocumentViewer cannot be found. Try the installation again using a valid copy of the installation package "DocumentViewer.msi".
If I close this window the along comes the Microsoft.NET Framework telling me "An unhandled exception has occurred in a component in your application. Click continue and application will ignore this error and attempt to continue." If I click 'continue" then a Windows Installer window comes up and then changes to the DocumentViewer window.