No plans for a Steam release
From Fudzilla:
From Fudzilla:
Despite the title showing up in the Steam database, Microsoft has been firm with their denial that Halo 3 is coming to the PC. The denial was as firm as it could be, with the company saying, “We currently do not have any plans to release any Halo titles on Steam.”Microsoft says no Halo 3 for PC
While rumors of a PC release have lingered for a long time, it could be that Microsoft was just trying to gauge the level of interest or that the company really has no plans to bring Halo 3 to the PC.