The last post in http://forums.techarena.in/windows-software/1401219.htm suggests making the font for the page headers and footers white in the Page Settings in Internet Explorer. But you might also try to set all elements in the right column (assuming the page numbers are in the footer) to empty.

If this is true, it seems that Windows Live Mail uses the page lay-out settings of Internet Explorer. I couldn't check, because I don't have the program.

Kees