No you cannot run Outlook Express on Windows 7. Because I have tried copying the program files from my Windows XP computer onto my Windows 7 computer and it does not work. And does not even work on Windows Vista.
However you can run Windows Mail for Windows Vista on Windows 7. Which I have installed on my Windows 7 and now on Windows 8.
Windows Mail is a lot like Outlook Express.
It is simple in appearance and works the same way as Outlook Express does. If you have a Windows Vista computer you can install on Windows 7. Just by copying the Windows Mail program files from Windows Vista onto Windows 7. You just have to delete the Windows 7 Windows Mail program file,on Windows 7 first.Which is inactive. And replace it with the Windows Mail Program file from Windows Vista.
You will need to download Unlocker from C.Net website or Take Ownership first. So that you can delete the Windows 7 Windows Maill program file. Before you can replace it with the Windows Vista Windows Mail program file.
And if you are installing Windows Mail on Windows 8 which is the same procedure as installing it on Windows 7.You must also copy the Msidcrl 30.dill dill file from the Windows/System32 folder on Windows 7. And paste it in the Windows/System 32 folder on Windows 8.
And that will get Windows Mail working on Windows 7 and Windows 8.
Or you could try Windows Live Mail 2009 version(not the 2011 version.) Like I use. I also use Windows Live Mail 2009,which is a lot like Windows Mail and Outlook Express.
Windows Live Mail 2011 is not,it has the Ribbon. But Windows Live Mail 2009 from Windows Live Essentials 2009 does not have the Ribbon. So I use windows Live Mail 2009 along with my Windows Mail.