The help viewer needs to make a change to the registry to make the application the target for ms-xhelp requests. To do this you need to run the HelpViewerRedirector.exe as an administrator (see below)
To install the application right click on the application and select run as administrator.
You will be notified that the registry has been changed
To revert the changes made to the registry by the help viewer just run the HelpViewerRedirector.exe as an administrator
On running for the first time the application makes the following changes
HKEYCLASSESROOT\MS-XHelp\shell\open\command
changes to the path of the HelpViewerRedirector.exe
HKEYCLASSESROOT\MS-XHelp\shell\open\ddexec\application
changes to the value HelpViewerRedirector
previous values of these keys are stored in a backup value.
To download the HelpViewer 1.0 booksonline for use with HelpViewer 2.0 and 2.1 run the application with the parameter download
HelpViewerRedirector.exe download
To install or uninstall you need to run the application as an administrator.
If you don’t you will get the following error