It's not a download; it's a part of Cnet, the website. (It spans across, Downloads, News, Forums, etc.) Just hit the little white arrow on the right edge of it to minimize it. That was a quick fix offered by the engineers after many of us complained the day it was first launched.
Hope this helps,
How do i get rid of that annoying cnet black bar at the bottom of the screen? I do not recall downloading it.