Firefox good – Internet Explorer bad

In Firefox my website looks fine. But when I tried Internet Explorer I noticed the main page doesn’t load correctly.

It is a three column theme. The problem I see is the right sidebar loads separately by itself way at the bottom right of the page making the page twice as long in size, instead of the right sidebar being next to the left and center columns as normal.

I was hoping somebody could take a look at the page and tell me what I need to do to correct it so it will show properly in Internet Explorer.

You can see the site here; https://www.digitechpublications.com

Any help with this would be appreciated.

Thanks