turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
To which yellow star are you referring? Is this a star that appears in your Notifications bar? If so, it's probably an app that has a message for you to view.
To find the message, on your homescreen follow Messages>(Menu Key)>View Folder and look through the folders until you find the source of the message. You can then delete it from there. Once you've dealt with the message, if the star still appears just remove your battery while your phone is powered on then replace it.
I hope that helps you. 
