Show hidden files option not working ??

Click Start  > Run… (or press Windows key + R)

Type regedit and click Ok. (if registry editor is also blocked, find the below lnk - http://mycompuhelp.blogspot.com/2011/04/enable-registry-editor-regeditexe-in.html)

Find the key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\SHOWALL

Look at the CheckedValue key. This should be a DWORD key. If it isn’t, delete the key. Create a new key called “CheckedValue” as a DWORD (hexadecimal) with a value of 1.

Now open My Computer, on the toolbar go to Tools > Folder Option and click on the View tab.

The Show hidden files & folders check box should now work normally.