halo crashes at start up

[positivity]

I had my halo to play H2MT maps then when my brother made a profile h2 crashed when he joined games.
Now I have re installed the game and it always crashes rite at start up. Please Help

 

[positivity]

I am sure it is caused from the changes made for running the modded maps.
Please help before i reformat my computer.

 

[| SCRAPY |]

re install the game and just go from there :/ do not reformat pc lol it is just the game is broken and should be reinstalled and stuff

 

[positivity]

re installed it many times with the same same outcome.Also my error not h2mt but halo2.5.