Creating 'Music creating software' with visual basic?

These last few days, I was searching online for music creating software, and well, they were all pretty expensive. So, as I'm a programmer, I've decided to create a music creating software myself, for my personal use, and as visual basic has very-easy-to-do GUI, I decided to create it with it. So I would like some suggestions, I know it's NOT easy, but I'm willing to try. So do you have any suggestions on how I begin, any guides on this, or even where I can get instrument sounds etc. Any help would be appreciated. Thanks!