Unable to play backward's compatable games on 360 with a brand new hdd

I recently bought an HDD for my XBOX 360 slim. It arrived today. I installed this using the method mentioned on this site as well as multiple hundreds of YouTube videos. Really, it isn't rocket science here. I even confirmed it's installation by going to
the system's tab, then to the storage tab. The Hard Drive shows up along with the memory unit and cloud saving, so I know the system recognized the hardware.

But knowing all that, any game I try, be it Halo one or two, or Fable, or Kingdom Under Fire: The Crusades, or anything else listed on the backwards compatability acceptable section, doesn't seem to work. It tells me that the game is unable to start, and
that I should either try downloading the game again, or contact xbox support team. I am using physical disks, so no download neccessary. Instead, I try contacting customer support.

Got some tool named El to give me stock responses for a few hours before he actually read my question or replys. Nothing he had me do helped, mostly because I had already tried those very actions. Restarting the system. Uninstalling and reinstalling the
Hard Drive and verifying it was working by going to the storage tab, just like I stated in the begining. Nothing helped.

El then assured me smarter more experienced people were on the case, and so far silence. So I ask the general audience. Any idea why a brand new Hard Drive for the slim won't work as intended?

:)