You will now want to double click on the 5th frame of labels, this will bring up a "frame Properties" box. In the text field enter the word start. Do the same for frame 25, but name it end.
Adding Actionscript
Now, double click on the first keyframe of preloader, and click on the actions tab. You will want add the following actions
If Frame Is Loaded ("end")
Go to and Stop ("start")
End Frame Loaded