If you want to mod halo and your wondering why it wont work...let me help you out
1.Download DOThalo(best program for modding)
2.go to the microsofyt Homepage(
www.Microsoft.com)
3.Search .Net Framework and Download the latest version
4.REMEMBER- while downloading, do not save it to a file or folder, instead simply open it.
5. Open up Dotahalo using Winrar
6.Mod on!
If this helped you, please give thanx