There is no Outlook Express for Windows 7.
Your options are to use MS Mail -- a web based email, which you can download as part of Essentials ( http://windows.microsoft.com/en-US/windows-live/essentials-home
), use Office Outlook, or my preference use Thunderbird ( http://www.mozilla.org/en-US/thunderbird/
). You can import all of your addresses, email, everything into Thunderbird from Outlook or saved Outlook files.