If running Microsoft Office SharePoint Server 2007 (MOSS 2007) and created a site from a collaborative template such as the Team Site template or Blank Site template, you may notice that by default you do not see the Advanced Search option to the right of your search box as you do when you create a Publishing Portal or Collaboration Portal.

Top Level Collaboration Portal Search Box

Top Level Team Site Search Box

To get started to use the Advanced Search, a page from which to perform your query and then another to display the search results should be there. MOSS 2007 has page layouts / template for each of these as well as provides customizable web parts to create everything completely from scratch to suit specific requirements. However the quickest would be to create a sub site using the Search Center template as this site template already contains the elements required. The steps are as follows:

1. From the home page of top level site, select Create from Site Actions menu.
2. Select Sites and Workspaces.
3. Fill in the details for new site. Make sure to select the Search Center template under Enterprise tab. And to inherit permissions of your top level site since it would ensure all users of top level site will be able to access the advanced search interface.
4. Click Create button to complete the creation of new search site.
5. It will be redirected to home page of new search site. The page displays a search box with a link to Advanced Search page.  
6. Click the Advanced Search link.
7. From the Advanced Search page, copy the URL of this page.
8. Select Site Settings from the Site Actions menu.
9. Because you are on a sub site to your top level site where the majority of site collection settings exist, you need to then select Go to Top Level Site Settings.
10. Select Search Settings.  
11. Select the top option and paste in the Advanced Search webpage. The URL  should end with /{the URL  name of search site}/advanced.aspx.  
12. Click OK.
13. When returned to the home page of team site, Advanced Search link will now appear & clicking it will load the Advanced Search webpage.