Some televisions will adjust the picture of M.O.J.O. so that the edges are off screen. To change this, you should check the settings menus of your television and look for Aspect Ratio or Zoom options. Every television is different so the exact method for adjusting will differ from model to model. However, if there's a Zoom level option then setting that to 'Full' should solve it. Alternatively, if it's an Aspect Ratio menu then 'Scan Only' is the option to select.
Be sure to update the firmware on M.O.J.O. if you haven't already. The firmware update introduces a modification to the way Google identifies the M.O.J.O. hardware which allows for many, many more games to be listed and downloadable in the Google Play Store. This modification makes it so you don't have to root the device anymore, unless you want to for the other typical customization benefits that root access allows. Rooting won't void your warranty.
If you went through our "Getting Started" walkthrough, you can use "ES File Manager" for accessing any files stored in your Download folder or on a USB.