Well, the sure sign the belt wasnt broken (atleast not that night at the light), is it started back up... If it dies, and then never starts again, yea it could be the belt... But it wont start back up... Unless it jumped a tooth, but thats doubtfull... And it would still run, just rough...

But we'd need a little more info... What does 'wont start' mean, does it crank, just wont turn over? Does it do nothing (like a dead battery?), does it start and then die? Ect...

Clanking noise dosnt sound good tho...