External drive showing wrong files

Hello,

i put some music on my external hard drive 3 day's ago and today when i loaded it up it showed the folder's but when i entered them all the file's had diffrent name's such as block's and such. i told window's to check for error's and it found none then after it did that now the folder's are not recognized as a type of file when i click on them they ask what to open it with, the folders them self's are now reading as only kb's amount of data in them but properties show over 600gig's still on it. is there any way to fix this? i tryed plugging it into a diffrent pc to see if it was the pc reading them wrong and the samething happen's.