Are you unable to get the "Open With" selection from the right click window, from inside your email program?

If that's the case, then just copy the attachment to your desktop, and right click. If you can get that "Open With.." selection, you can reassign that kind of file to word.

Another thing to do is copy the attachment over to your desktop and then just drag and drop it onto the Work shortcut icon (if you have one on your desktop, if not, just create one).