Use the following steps to prevent your games and hard drive from becoming corrupted. Go into the Xbox 360 Dashboard and scroll all the way towards "System". Once there, go to "Memory". Select your hard drive or memory card, then select "Games". Go to the game that may be giving you trouble. Scroll through the game's saved data. If you see a yellow triangle with an exclamation mark inside it along with the word "Corrupted", select it. Once it comes up, select "Delete". You will be prompted "Are you sure you want to delete this file?". Press A to confirm and this should fix any problems you may have had with that game, and will also keep data for other games from becoming corrupted.