C program

I need help writing a progam very similar to a musical keyboard. I don't want to use midi files though. Nor do I need to play the sound through an embedded speaker. Basically I need a program that recognizes that a button has been pushed (using a PIC18F4455 or 4550? microcontroller) and sends that information via a USB to? a PC to play a sound file (preferably a .wav). We will start with the sound? basics and then work our way into LED'S! The programs used need to incorporate MPLAB and? C. Coders knowledge of circuits would be super helpful? for this? newbie buyer.? Buyer will probably need some handholding!