MS aren't having any DEVELOPMENT involvement with Halo, they DID however announce a PC version to the world and said that Gearbox had the task of doing the conversion.
So that says to me that they had SOMETHING to do with it, wouldn't you say
And Bungie, despite what you may think, have no say in it anyway.
And what happened to the original code ?
After all, I saw the thing *running* on a PC a couple of years ago.