While there is no option within Outlook Express to turn the splash screen off, you can remove it via the system registry.
Turn Off the Outlook Express Splash Screen
To turn off the splash screen when starting Outlook Express:
- Select Run... from the Start menu.
- Type "regedit" (without quotes).
- Press Enter.
- Travel down to HKEY_CURRENT_USER\Identities\(Your Identity)\Software\Microsoft\Outlook Express\5.0.
- Select Edit | New | DWORD Value from the menu.
- Type "NoSplash".
- Hit Enter
- Double-click NoSplash.
- Enter "1" as the value in the dialog box.
- Close the registry editor.