why mail is removed from windows-7 is it unnessery or making harmful for system?

What used to be called Outlook Express is now incorporated into the Windows Live experience. Just download Windows Live and you'll have MS's version of mail.I hope that answers your question to your satisfaction. If you're asking why MS chose to not include OE into Windows 7 then I don't know the answer. And Idon't really care, one way or another, either way...I never did like it much and find that I can actually use the Windows Live version much easier.Regards from the Valley of the Sun.