how to obtain SQL Server FullText Search service?

I did a full installation of SQL Server 2008 Express. Looking at Add / Remove Programs, I see the following pertinent programs installed:

SQL Server 2008

SQL Server 2008 Browser

SQL Server 2008 Management Objects

SQL Server 2008 Native Client

SQL Server 2008 Setup Support File (English)

SQL Server Compact 3.5 SP1 Design Tools English

SQL Server Compact 3.5 English

SQL Server Database Publishing Wizard 1.3

SQL Server VSS Writer

SQL Server System CLR Types

 

And of course I also have installed .Net Framework 3.5 SP1.

 

I'm now trying to obtain sample SQL databases. To this end, and by the advice of others, I'm trying to install SQL2008.AdventureWorks_All_Databases.x86.msi. But whether I try to install "Sample Files" or "Create AdventureWorks DBs", I keep getting the following error:

 

PrepInstance() failed for MSSQL$SQLEXPRESS.

The following features are missing: Full Text Search

 

Running services.msc shows the following local services (but not SQL Server FullText Search):

SQL Active Directory Helper Service

SQL Server (SQLEXPRESS)

SQL Server Agent (SQLEXPRESS)

SQL Server Browser

SQL Server VSS Writer

 

Does anyone know how I can obtain the FullText Search service for SQL Server 2008 Express?