Checkout Page Query

[stcole]

In my site I sale some of my personal products. In the checkout page I am getting most of the users exiting my site. So I showed to an expert. He told me that the scrolling down action on that page is responsible for all the exits. As users if have any error they have to fill the entire form from top to bottom by scrolling down. Here is the problem I really need users to fill the entire form. How should I resolve the matter here? Please help me with your valuable suggestions.