Starting with the last question: then there is something wrong with that install/theme.
(Just checked, and it should search the whole WP blog)
For displaying only the titles – you’ll need a special template file, search.php
. If I remember well it is documented somewhere in the Codex, but basically you remove the_content tag and everything else you don’t need from the template; you can start by saving your index by the name above and edit it.