adding varying content to pages on site

I have just installed word press and I am using the WP theme on the site. I have multiple pages on the site and I would like all these pages to have different stories and links to topics related to the page rather than have the same links displayed on the sides of all the new pages. I need to have at least 10 pages with each page covering a variety of stories and a lot of content. So do I need to change the theme and use a theme that allows for every page to be modified or do I have to install 10 websites of wordpress and set uplinks to those pages pointing to the Virtual Directory. I am running everything on my own server using Windows 2003, IIS6, Php 5, and Mysql 5. Any help appreciated.