If you are using OS X to work with audio editing then I'd suggest GarageBand. If you are on Windows... No clue. Since you are learning the hard way, then keep in mind that you should watch some great machinima, and understand what went into them, and what elements make them great before proceeding making your own.
Only use Movie maker, and make sure to only use the approved blue backgrounds with white text for credits, intermissions, anything. The following music is appropriate, no matter the scene:Crawling in my skin- Linkin ParkLet the Bodies hit the FloorSound System 009Bleed it outDubstepHeavy MetalBreath into meGreat divide- Linkin Park