1. Open Command Prompt as Administrator
2. Type attrib -r -s -h f:*.* /s/d
(change f with your external drive letter)
3. Tap enter, wait for a moment
4. Voila, you have your file comes back
Yah, you almost hit it, dude.
It's a virus! That hides your files.
So just tell your computer to show them again, therefore...do THIS.
In the Windows Command Prompt:
-Write: d: (change d with your external drive letter).
-Write: attrib /d /s -r -h -s *.*
-Wait for your computer to work. It's ready only UNTIL this appears: "D:\>_ " (My computer took a long while).
-Go back to your HD and see.