IE6 Messes Up Sidebar

Can anybody help me out?

You should first validate and fix your code (it has errors):

https://validator.w3.org/

Then check your css (style.css) for the sidebar and main content column width, margin, and padding, which may add up to too much for the containing div, causing your sidebar to be pushed down and out of the way. Also check that your content (images, etc.) is not too wide for your containing divs.

https://api.browsershots.org/png/original/13/1383294a5d85c4c57798b5fbbad7de1f.png

I validated and it shows up like that now.
What do I do now?