Windows 7: Win7 - WD hard disk size disk is right but 2 folders not showing

hi

i have a 1 Tb WD external hard disk . i had 2 folder conatin about 700 gb , but now these folder not showing and i used show hidden files and show operating system files but not showing .

i found that these two folders are in the J:\.wd_tv\thumb

and my files are there , but they are in .tumb files , for example if i had a file with name aaa.mkv now it`s aaa.thumb and if it was 4 gb , it`s now 50 kb for example.



many of my files are like this and many others not showing , what`s the problem ?

i think i can get my files back because , the size of them are exist , please help me