Registry path to enable or disable "Show Hidden Folders" in Folder Options.
1. Open Regedit through run.
2. Navigate to the path:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
3. Change the value of "Hidden" to 1 inorder to enable and viceversa and restart the computer to apply changes effectively.
This works for Vista,7 & 8.