A family of Microsoft word processing software products for creating web, email, and print documents.
To remove a header, you have to insert a section break at the end of the preceding page (Page Layout tab | Breaks | Next Page) and then enable the "Different first page" option on the Header & Footer Tools Design tab (which will be active if you double-click the page header).
To remove page numbers, you also need a section break, or you'll need two section breaks if you want to remove the page numbers from one or more pages in the middle of a document. In the specific case where you want a front matter, see http://word.mvps.org/faqs/formatting/front_matter_2007.htm.
Be aware that text won't flow from one section to the next. Each section is a separate "container."