First, uninstall the software using Add or Remove Programs feature:
If you use Windows XP or bellow you can go to Start > Control Panel > Add or Remove Programs. In the Currently installed programs box, click on the program and then click Remove.
If you have Windows Vista or above you need to go to Start > Control Panel > Programs > Programs and Features. Select the application and click on Uninstall.
In order to install it again, close all programs, insert the NTI Media Maker CD in the appropriate drive and click Setup to begin the installation. Press Next, read the License Agreement and click Yes to accept the terms and to continue, enter your name in the User information window and click Next. In Choose Destination Location window you can change the installation folder. Press again Next and restart your system. If you still have issues, you need to contact the developer.