Campaign wont start. need help :S

i just borrowed a copy of halo 3 from a friend so i can try out the campaign. but for some reason the game wont allow me to start it. The game loads up as normal, i select ‘start solo game’, it freezes for a sec and this screen pops up:

then it takes me to a campaign lobby. but still doesnt allow me to start the mission. it shows this:

what the hell is going on?

You have a broken disc.

> You have a broken disc.

broken disc? but the game still loads normaly

You probably do have a broken disc :confused:

Check for scratches on the disc, some places can fix discs if your friend is willing to hold off playing it for a week or two.