I installed the star trek elite force 2 video game, but I had to uninstall it using the Revo uninstaller program. I tried to install the videogame again, but when I insert the cd-rom in the reader, I click on the launch and I only see the possibility to uninstall the video game. Can anyone help me ?

Look for it in "Control Panel -> Programs and Features" and uninstall from there maybe. I feel like you should still be able to install it, even if it thinks it's already installed by launching the setup from the CD manually instead of going with the Autorun program. See also this https://www.moddb.com/games/star-trek-elite-force-ii/downloads/how-to-install-ef2-correctly-on-windows-7