Run the o2mania.exe or Launcher.exe . Once the program opens, click "File" (or press F8 ) to browse your song library and start playing. Why the Community Prefers 1.4.2
You can find the English 1.4.2 executable through community archives or repositories like Software Informer or Wakelet . o2mania english 1.4.2
The simulator usually doesn't come with music. You will need to download "song packs" and place them in the Music or Songs folder within your O2Mania directory. Run the o2mania