Hello ....
IMPORTANT ************************
FIRST backup your registry .... using ERUNT
http://www.larshederer.homepage.t-online.de/erunt/
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Now
Go to Start >> RUn >> regedit >> navigate to ...
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advan ced\Folder\Hidden\SHOWALL
Now right click on,and delete the value "CheckedValue" in the right hand window.
Now create a new "DWORD Value" called exactly CheckedValue in the right hand window.
Double click on CheckedValue.
In the opening 'Edit DWORD Value' box,set the 'Value data:' to 1
Press Ok,exit regedit,restart your pc.
Hope this solves your problem