Keep the game from using controller?

I use a Nostromo speed pad for playing games. I map the keys there to the keyboard. The game keeps thinking it's a regular xbox controller and takes inputs from it that aren't what I tried to map to the keyboard. Is there a way to get the game to not look for a controller and just accept keyboard commands?

https://www.x360ce.com/ you could try using this to emulate an xbox controller
or, if the controller is detected as an xbox controller, maybe you can use durazno to remap the controller buttons https://github.com/KrossX/Durazno

is there an xinput .dll in your halo 2 folder?