Halo 2 is a game developed by Microsoft Game Studios for the Xbox and ported to PC. It was intended to be played on Windows Vista and Microsoft didn't care to make it work with future versions of Windows.

Issues

The procedure entry point DwmIsCompositionEnabled could not be located in the dynamic link library C:\WIONDOWS\SYSTEM32\d3d9.dll.

After installing Halo 2 and trying to run it using either the startup.exe file or the halo2.exe file the error pops up.

Solution

Open the Halo 2 folder
Delete the file dwmapi.dll