To enable full text search you will need to do the following..
1) Upgrade the SharePoint named instance of SQL to full SQL Server 2000..
be sure that you install/add Full-Text Search.. (listed in the steps in the
premiuminstallsteps.htm on the Premium cd)
2) Once SQL Server the named instance is upgraded and service packed, then
go to Start/Administrative Tools/SharePoint Central Administration scroll
down to the Component Configuration section and click on the Configure
full-text search link. Then click the checkbox to enable full-text search
and index component..
Once that is done if you then go back to the companyweb site then you
should see a text box in the upper right corner of the page (with a
magnifying glass icon to the left.. ) to enter your search criteria.