I've seen similar posts to this but the solutions are not paying off in this case. I've made a subtheme of Omega html5. My front page is fine, other nodes have the right sidebar sitting under the left sidebar. In instances where the Content is longer than the left sidebar, it wraps to the left between left and right sidebars.
I noticed this after creating a slideshow view for my articles. Though I'd also been doing other things such as moving blocks around and messing with the global.css and creating content types and menus. So I can't really point to one thing that happened to crash this.
I've removed the styles I put in the global.css file, and I've turned off each block one by one ... no change. I've tried site validation tool and the css has a lot of issues that seem to be irrelevant except maybe that some items have no class even though the attribute is called up:
e.g. "Line 440, Column 87: there is no attribute "CLASS"
…ypeof="sioc:Item foaf:Document" class="node node-news-item node-promoted node-…"
But if that's relevant, I'm not sure what to do with that.
Interestingly, if I have the Blocks debugging blocks visible in the admin view, it shows a debugging block for both the left and right sidebars but NO DEBUGGING BLOCK for the content. The content of the content block is there though.
I updated from 7.9 to 7.10 yesterday to see if that would change anything but nothing changed.
Any pointers would be appreciated.