Wow, that's was an amazing game, i clicked on this thread and started playing then everyone in my xbox live party asked me what i was doing so i told them, they all got on their laptops and started playing at the same time, it took us about an hour to do it, but we finally escaped the room!!!
I don't wanna post any spoilers so if anyone needs any help post away...
To one of the posts above the piano keys are:
C D E F G A B
So look in the briefcase at the 'colour corresponding to the letter' and type that in as the code, if a letter on the kayboard has no colour then leave it colourless