Use regedit Under HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionExplorerFileExts Deleting the sub-key with the same name as the extension and restart. Link
ShellMenuNew Very Easy to use
XP Path Vista and Windows 7 Path All User Desktop All User Desktop %systemdrive%Documents and SettingsAll UsersDesktop %systemdrive%UsersPublicPublic Desktop All User Start Menu All User
set the value to true restart firefox
Command prompt sc delete <services name> Reboot Windows Registry regedit Navigate to HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServices Locate the services on the left pane and right click and delete
>Windown Key control userpasswords2