So my school does a Halo one LAN every year and I dont meant to brag but im pretty good at halo and im confident that i could dethrone the current champ. Problem is I cant play with a mouse and keyboard and school starts in a week so thats not really enough time to learn to play with it so i was wondering if i could just plug a 360 controller into the pc and play or if i have to download some stuff to play with it.
Looks like Microsoft actually have a KB article for it, see if this helps you out OP:
https://support.microsoft.com/en-us/kb/909385