halo 3 odst, unlike halo 3, has no matchmaking, sorry
By gaining XP
you get one xp per win
2xp
You get XP by winning matches in matchmaking. If you lose the match, then you lose XP. Simple.
halo 2
Halo: Combat Evolved runs just fine on Windows XP.
in one ranked playist get 25 xp
win, and go positive for that round... is that really how you earn xp ?
To boost on Halo 3 or Halo 3 ODST, you must change your language to anything that your not using right now. Have a friend join your session and he'll be on the other team. That way you can get infinite XP. :)
Yes. You can.
so far i have only seen it in a doubble xp weekend playlist.