X-box 360 - Deleting Game Cache

[Cathiron]

I know it's an old favourite but following on from the Fable II freezing problems I decided to try and delete the game cache but don't seem to be able to find it. Ive followed Microsoft's instructions but cannot highlight the far left game icon and therefore do not get the "delete only" option. What am I doing wrong please? Do I have to delete the game save first before I can delete the cache? Any help will be much appreciated.