Show/Hide file extensions

One way is to do it using folder options. The registry way is as follows: To Hide: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced] "HideFileExt"=dword:00000001

To Show/Unhide: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced] "HideFileExt"=dword:00000000