Microsoft doesn't make or support Outlook Express anymore. But the Mail Migration add-on can help you move your email and contacts over to Outlook.com. The add-on automatically moves your email and contacts, and you can keep your current email address. If you want to use another email address as your main one, the add-on will also help you set that up.
If you haven't had success moving your mail, you can contact Microsoft support for help. Launch our support app to see your options or contact an agent.