On some 64 bit computers the MS Dynamics GP install will hang.  Typically you cannot uninstall the program.  Running setup.exe again will launch but when clicking on the install MS Dynamics nothing happens and the screen clears.

In this case you have a partial install.  Attempts to load a service pack result in messages like “Property invalid country code”, and installation of the service pack hangs.

Although you might think this is a rights issue with the user not having Admin rights or a .net issue it most likely is not.  First you should properly uninstall MS Dynamics GP.

Download the MS Fixit program from this link.  This is a download of the pointer to run the program from the MS server.  So you must be online to run the tool.  You cannot download the tool and run it offline. http://support.microsoft.com/mats/Program_Install_and_Uninstall

Follow the prompts to Uninstall the program.  Do not try to fix the MS Dynamics installation.  Uninstall first.

Rerun the MS Dynamics install, right click on the setup.exe and run as Administrator.