I apologise about the delayed reply, I haven't checked here for several days.
Could you please describe what exact problems are you currently encountering? Does the game crash with error messages when launching it, or does it simply refuse to launch at all? Are there any other problems and was the installation process of the game successful without any issues? There may be multiple reasons for why the game does not work, and so it is imperative to localise the symptoms and potential issues first.
Generally, the troubleshooting article contains all the essential information for resolving the common issues with the original UA. So it is highly recommended to check this page:
Windows Troubleshooting - Metropolis Dawn Beta
Alternatively, you can also always use OpenUA if the original game does not work properly. For this, using the ready-made package called 'OpenUA Standalone Package' is recommended. Further information is available at here:
OpenUA (UA:Source) - Metropolis Dawn Beta
The standalone package does not require any further tweaks, and it already contains German language and voice data files, but the in-game cinematics are in English version (the individual movie files take up a substantial space, and so we decided to only include English version by default and left out German/French/Japanese UA versions of movie data), which you can replace with the German UA movie files if you have the original German UA CD.