solution

If still cant, try this:

Open your registry and find or create the key below.

Create a new DWORD value, or modify the existing value, called "Hidden" and set it according to the value data below.

Exit your registry; you may need to restart or log out of Windows for the change to take effect.

Registry Settings

User Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\
Advanced]
Value Name: Hidden
Data Type: REG_DWORD (DWORD Value)
Value Data: (1 = show hidden, 2 = do not show)

else try this:
Go to the following registry key:
HKLM\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL

DELETE the value CheckedValue in the right window. (Its type should be REG_SZ and data should be 2.)

Now create a new DWORD value called CheckedValue (same as above, except that the type is REG_DWORD). Modify the value data to 1 (0x00000001).

This should let you change the "Hidden Files and Folders" option.