You can't use same id for 2 divs on same page.Try like below:
<div id="videos3">
<iframe frameborder="0" width="460" height="255" src="http://www.dailymotion.com/embed/video/Your3rdvideo"></iframe>
<img src="images/comingsoon.jpg">
<div class="clear"></div>
I hope this will help to you.