In my first computer I clicked on software center,scrolled to LibreOffice Base and made 1 click to open Base(as I recall). On my 2nd computer I clicked on software center, scrolled to LibreOffice Base and a click brought up 'Available from the "main" source'. What did I do wrong and how do I open applications in the Software center?(no terminal scripts). The same CD loaded both systems. This edit is to say I just remembered my 1st computer was on line and the 2nd was not. When I got the 2nd computer on line the application loaded OK. I do not know the procedure for responding to the answeres so let me say they are appreciated.
Ubuntu Software Center is not used for running applications. It is for purchasing, installing, and removing applications. If you want to run an application that is installed, simply open the dash by clicking on the Ubuntu logo on the top of the left bar (launcher), and you can search for the application, and run it. Or you can switch to the
LibreOffice Database is not installed by default on 12.04. You must install it before you can launch it. The software center is for installing/uninstalling applications, not launching them. To launch an application you can use the "Dash Home" button on the unity sidebar.
[Links below will need http:// placed in front of them. I'm not registered so I can't post this many links]
Launch A Program Via Gui On Ubuntu 12.04 - Desktop X86-64:
Click on "Dash home".
Enter the program name to search for it.
Click on the desired search result to launch the program.
Wait patiently for the program to open.
You have successfully opened the program and can begin using it.
Install A Program Via Gui On Ubuntu 12.04 - Desktop X86-64:
Click on "Ubuntu Software Center" on the Unity sidebar.
Search the name of the program you want to install.
View search results to single out the desired program from the results.
Click on the desired result. Click "more info" (or you can click install if you are sure it's what you want).
After viewing the program description/reviews/screenshot not all of which may be available, click "install".
Wait patiently as the program (downloads and) installs.
When it finishes installing it will say "installed" and an option to "remove" will become available should you ever wish to uninstall the program.
Some programs have addons available for them, scroll down to see the list and install any you desire.
Check the box(es) for the addon(s) you want, then click "apply changes".
Wait patiently while the addons are downloaded and installed.
The page will once again say "installed", you have successfully installed the program you want, as well as any addon's you wanted.