'show hidden files and folders' option not working

press windows+R >> type "regedit"(without quotes) & press enter >> then go to>>

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\SHOWALL\

Now u can see two keys CheckedValue and DefaultValue

Double Click on CheckedValue and set the value 1 from 0
Double Click on DefaultValue and set the value 2 from 1