I think if i understand your question, you do not need software to accomplish this...
you are copying "plain text" (just words no hidden nonsense) onto a "email" (which you send with the program outlook express)
Here is a pretty good "way around this" "without buying new software"
after typing your letter in word, select it all and hit "copy" (located under edit>copy) then open a new word document (just a clean page) and go and "paste it with unformated text". to do that, go to edit>past special> then select unformated uniacode text.
you will see... the page look very much the same, only difference is if you used any color, or different size font, it went away.... simply copy this plain text (now it really is nothing but text) and then paste it into your email.
Now, if all goes to plan... you should not get any weird unexpected "active X" problems.
(the only other problem that you might have is if it is not extra script you are sending that is causing this problem.... then you might have a virus that is adding content to your email,.. and using active X to spread itself... in that case, make sure your anti virus is up to date, or better yet talk to your local computer guy and he will take a look at it...)