I just put in a new 80gb HDD in my XBOX and I transferred over the contents of my old HDD but I screwed some stuff up. What I want to know is how can I make it its a completely clear HDD with just the default XBOX system files on, basically like its a brand new normal HDD only with more space. I'm using the X3 modchip.

Since it's chipped, just use an autoinstaller such as Slayer's.