Go to your Joomla! 1.5 Administration (Backend) eg. www.yoursite.com/administrator and login with your username and password
Click on Content -> Article Manager
No you’ll see all your Articles listed, you’ll see the title Front Page and underneath that you’ll find there is either an Red Cross or Green Check Mark next to the Articles, if there is a Green Check Mark it means that the Article will be displayed on the Front Page. Click on the Check Mark and then you’ll notice it will turn into a Red Cross which means it’s not displaying on the Front Page.
Alternatively you can also click on Content -> Front Page Manager and then under the title Published you’ll notice a Content Icon with a Check Mark on it next to the Article. Click on it to have it unpublished and now it won’t appear on the Front Page.