I'm having the "Empty Folders" problem with my External HDD.

Hi, I'm currently having a problem with my External HDD.


My OS is Windows 7 Professional, SP 1. 64bit.
the HDD device is Hitachi H3640US, 600GB model.


Recently it started showing all the folders empty. When I reboot the device, the first 2 minutes or so I have access to all files, and they are visible.
However, soon all the images and videos start becoming completely invisible (Folder Options switches on Show Hidden Files on and off are not working at all)


I've tried attrib -h -r -s /s /d g:*.* and the results display messages as:
"Unable to change attribute - G:\[file or a folder name here]"


I can't scan it with my Avast Antivirus, nor Malwarebytes at all, because the programs can't detect what's inside.
Windows 7 Disc Check also doesn't work because it runs out of the accessible time to the files.


I guess it is a severe malware problem, what should I do to fix this problem?