MIDI Help

I've been working with VB6 for a few years now, so I'm not exactlynew to it. However I am starting a new application but I don't eally know how to start. Essentially what I am doing is mking a program similar to "Guitar Pro" I'm not sure if anyone is familiar with this app so I will briefly explain it. What Guitar pro is, is a real-time midi player. It emulates guitar sounds through midi by means ofa user yping a number on a virutal guitar string and when you press play it renders the midi without any pre-determined hard-coded presets. So, here is my question. Can someone tell me the simplest way to render midis in run-time depending on what a user has typed? It would be greatly appreciated, thank you.