I'd heard that there was a potentially gamebreaking glitch in The Legnd of Zelda: Skyward Sword, so I made sure to check it out to make sure I didn't fall prey to it, and wanted to share the info with any of you who don't already know about it to save you the hassle of having to start all over again.
Basically, if you go for the song of the Thunder Dragon before the Fire and Water Dragon songs, you could potentially trigger a glitch that will make it impossible to complete the Fire and Water Dragon songs and therefore the game itself. The glitch is activated by going to the Lanayru Desert, speaking to Golo the Goron in the mine, completing the Thunder Dragon's event and receiving his song, and then speaking with Golo again before heading to the forest or volcano regions for the other songs. If you do that, the forest and volcano events won't happen, so you can't continue with the game.
I find it strange that Nintendo says that you either have to start the game over again or use an earlier save file since you're only allowed one save file in Zelda games. Basically you have to hope that you didn't save before starting the quest at all. Which at least for me, probably wouldn't have happened, because I save constantly.
Honestly, the best fix is to simply get the Fire and Water Dragon songs first, and go to the desert last. That's what I plan to do when I get to that point in the game, so as to avoid the issue entirely. Never have I been so glad to have slowed down my progress in Skyward Sword to complete another game! I know that some people are hoping Nintendo will release a patch, but they tend not to do that very often. However, with a AAA title like Skyward Sword, maybe they'll make an exception? I'll let you know if I hear anything.
The Legend of Zelda: Skyward Sword Has A Game Breaking Glitch - Nintendo Responds [G4tv.com]