So my friend and I like to play LAN worlds together in survival and we had this really good survival world going in 1.5.2, because their computer is only compatible with 1.5.2. One day I went into my single player worlds and it was gone! Poof gone. So I went into my saves folder, and it was still there! So I took it out and put it back in, and it still doesn't show up in my minecraft single player worlds. I know it didn't get renamed, and I'm pretty sure I didn't delete it on accident, so PLEASE help.
Cheers, MaliciousBanana