I'm trying to help you out here. You just have to answer my question, how much room does your G drive have?
And Yes, all you need is the xbox and a game.
There are 2 different dashboards EvoX, and Avalaunch (there are a whole lot more, but those are our main focus). My best guess is that you have a evox bios and a avalaunch dashboard. I'm not familiar with the Avalaunch dash, but there should be an option to copy games to the HDD. If you cant find that option then you will have to manually install the games. I can tell you how to install games manually, but I REALLY need my question answered before we go any further.