how to add full text search services in already installed instance of sql 2008?

when I try to download adventureworks sample database, it says no full text service availble and ask to install it before installing sample database. I google but could not find the way except one for XP envronment where someone was suggesting to activeate some deamon services and install . but mine is windows 2003 and I could not find that services in my system.
I went through control panne add remove programs to add but stops once it could not find the full text service

Can somebody tell me how can I add this full text services in my existing instance of sql 2008? I do not want to reinstall the whole sql 2008 engines.

Thanks

Which edition of sql2k8 you have?

I have sql 2008 Enterprise trail version .

Let me know if somebody has any tips for me regarding my question above.

Thanks

Did you choose full text index when install sql2k8?

while installing sql2k8, I did not install this component of full text search features. and now when I try to play with Adventure works Data warehouse installing it, it ask for th is full text features service. Now I am looking for a way to install this full text search service in my existing instalnce of MS sql 2008 so that I might be able to attach or install this sample adventure works database.

Thanks
Santosh