There are template problems with your Yoo theme.
eg.
<div id="middle" style="min-height: 5592px;">
<div id="mainmiddle" style="min-height: 1979px;">
Which makes a very long content section.
Also the product text has been entered by copying and pasting from a word processor so you have a load of junk style code which could contribute to your problems.
eg.
<h2 id="product-description" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0.75em; margin-left: 0px; padding-top: 20px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; border-style: initial; border-color: initial; font-weight: 500; font-size: 20px; font-family: tahoma, arial, sans-serif; color: #3b3b3b; clear: left; border-width: 0px;">Apple MacBook Air Laptop Product Description</h2>
<div id="product-description-container" style="border-style: initial; border-color: initial; font-family: 'Nimbus Sans L', tahoma, arial, sans-serif; color: #3b3b3b; line-height: 16px; border-width: 0px; padding: 0px; margin: 0px;">
instead of:
<h2 id="product-description">Apple MacBook Air Laptop Product Description</h2>
<div id="product-description-container">
Do not copy and paste from any word processor - use a good text editor and then format/style the text using Joomla's editor.