After the latest release of Halo 2 Annivil on PC, it seems that 343 Industries hasn't stopped working to add new titles to the collection, Halo: The Master Chief Collection. Now that they have spoken from the Halo Waypoint blogHalo 3 testing will begin in mid-June.
If you want to participate in a Halo 3 test, or in a future test, whether Halo 3 ODST or Halo 4, you must register with Halo insider show
Halo 3 testing is starting
This way you can test games before their release on PC and be able to assist in finding the errors and report them to the development team. Failure is where the saga is leading in its evolution to PCs when 343 Industries is already working to fix it, as recently happened with the release of Halo 2 Anniumph.