PLEASE HELP

So i'm new with my mpc, been choppin up samples and they've been playing....then one day non of my samples will play, they are there, when i play them its just air that comes air, i think my firend did something and now they won't play...any ideas please??
thanks

anyone?

could be anything... you getting any sound output from it at all? You made sure youve loaded up the program you was working with and that youve got that program selected on the right track? Have you tried headphones (to rule out any problems with the main outs)?

in before the lock