So, I went on my computer today, and my Minecraft pc world was corrupted, and wouldn't show up in Minecraft. After searching, I decided that I should try to find the seed of the world, so I downloaded NBT Explorer, but when I opened level.dat, it says "One or more selected files failed to open." I have no idea what to do, and I really want my world back. Also, here's a link to a zipped copy of the corrupted world: http://www.mediafire.com/file/tr8jvnaqy6a8jl2/No_cheating.zip
I have also tried repairing it in MC Edit, but the option is grey and won't work. Edit and View just come back with an error.
I attempted doing what @sh4dow said twice. Once, it brought back the world, but nothing that I'd built was there. The second time, it did nothing, but when I viewed the world it was in with MC Edit, there were chunks missing, like a chessboard.