Xbox 360 Hard Drive Missing Space

My Xbox 360 came with a 20gb hard drive, but it seems to have shrunk over time.

Yes, I know the drive really only ever had about 13 gig of usable space, thanks to Microsoft taking up the rest of it for who-knows-what. But it’s worse than that.

The Memory page of the dashboard shows that I’m using 4.7gb for Games, 14mb for Gamer Profiles, 0kb for Demos, 569mb for Videos, 51mb for Themes, 7mb for Gamer Pictures, and 6mb for “System Items”. That adds up to about 5.4gb. I have no music on the system.

The system says I have 3.4gb free. 5.4gb + 3.4gb = 8.8gb. I’m missing about 5 gig of space.

So I have 3.3gb free, and I need over 6 gig to copy Call of Duty: World at War on to the hard disk. Where did the rest of my space go?