Since we are trying to trouble shoot a problem, it helps when you are able to provide some details.
What I am trying to determine, is Does the program Start at the end of the Installation process? It should.
When you say "will not launch", I have to Guess that it will not Open, when you click on an ICON on your Desktop / Computer.
Are you seeing ANY Error Messages or Warnings?
Please go to the new Knowlege Base website athttp://ancestry.custhelp.com/
and enter 4848 in the Search Support box on that page. This is to Manually Uninstall Family Tree Maker.
Then, read Article 4953 to Install.
Please don't forget, that IF you are using Windows Vista or Windows7, that you need to do the installation using the Run As Administrator feature of Windows.
Hope that helps,