I have Ubuntu 11.10. When I installed it I could see my applications, but anytime after installation, I can't see my applications and I can only use the aplications that I have in my laucher.
Hare's how to browse all the installed applications in Unity!
Press Super Key (Windows key) or click on the top most button in launcher to open the Dash.
Just scroll down and you'll see all the applications installed on your system.
Click on the Dash Home (Ubuntu logo on the top left corner) and type the application name.The Dash will show your application, just click on it, see it launches.You can drag and drop the specific application icons to the launcher for easy access as well.