Open the extracted folder and look for a file named Setup.exe , Unpak.bat , or Inject.exe . Run it as an Administrator.
What (e.g., Windows 10, Windows 11) are you running? Assassin Creed 1 Highly Compressed Pc Game
Some repacks will automatically install or prompt you to install DirectX and Visual C++ Redistributables if they are missing. Allow these to install when asked. Open the extracted folder and look for a file named Setup