I cannot start playing games

If you're playing the game, it cannot update. Don't start the game when it says ready to start, leave it until it's finished

Cannot wait to download Peggle 2 and start playing. If it's anything like the first game then I will lose many many hours playing this.

First, if you see the "assigned to another console" message, just follow these steps:

1. Sign into your new console, or if you have more than one console, the console in which you are trying to make your primary console.
   
2. Send an item to your download queue.
3. Go to your active downloads. To do this, press the "guide button", then "marketplace", then active downloads".
   
4. Select the item and press "A"
5. Choose the second option, "download all items". Choosing this option makes this console your primary console and the problem will cease permanently.
   

As for Destroy All Humans, are you referring to the original Xbox game, or the new Xbox 360 game? If it's the original game, please refer to

this sticky regarding playing Originals on your 360 console.

There is no way to check for firmware but odds are the drive is probably a 3rd party one even if it's labeled as official (these things happen).

The best way to check is download the game to a console with an official drive or purchase an official drive to redownload the game to. The only way to be sure you're getting an official hard drive is to purchase from a legitimate source such as GameStop,
etc.

Sorry to hear it. Where did you purchase the hard drive from? If it was from an online retailer such as Ebay or Amazon the drive may be a 3rd party drive which do not have the required firmware to run a backwards compatible game.