Cross Capatable

It's up to the game developers if they want to do that.

Not just that but it requires completely different hardware (lazer ) hd dvd and bluray werent capatible with each other the lazer lengths were different

They were both backwards comaptible but not cross compatible otherwise the standards wars would.be still on

You cant stick a hddvd disc in a bluray player no matter how much money you throw at it

Hi, joshlarose

as R4GE vKiwi has mentioned, try resetting your Xbox and see if that fixes it

Let us know how it goes.

Hi, try restarting your xbox.

Try re-downloading your Xbox Live Profile while on an Xbox 360 Game.

First, load the game of choice, (in this case, Modern Warfare 2), then, simultaneously press Menu, and Select, (the two buttons to the right and left of the middle home button), this will bring up the Xbox 360 Interface.

if you already have your profile installed, dont worry. Simply press X to sign out, then, hit the option labeled “Sign in”. Scroll to the bottom until you see “Download Profile”. Input your Xbox Live info to sign in, and let it download. Try to log in again,
and if it still does not work, i recommend contacting Microsoft Support at the following link.

https://support.microsoft.com/en-us

Best Regards!