i know this is a stupid question but whenever i click on my haloce application , it wont open. it use to open but i switched it onto another computer user profile. now it wont work, and i already deleted the old user account in which the haloce folder was first located... it wont load, everytime i click it it wont open. i right clicked it > chose open but nothing happens. why?

that happened to a other guy i know. It happened cos another user on that pc tried to play it and it got stuffed for some reason. So i had to give it to him again and it now goes fine. Maybe when you deleted your old profile, it took halo with it? I suggest redownloading.