Something goofy's going on with my template

OK, something goofy's going on with my template. The "recent posts" list should be a sidebar column beside the current post(s) rather than above or below ... along with my profile information. I've tried switching up templates to correct the problem. With some, the "recent posts" sidebar doesn't start until way down the page below the currently active posts. With others, it's the other way around. The current posts don't start until below the "recent posts" sidebar.

I think it may be something I inadvertently did to the html code, but I don't remember editing it recently. When I do edit it, I do so very carefully because I don't know much about it.

I had some significant trouble getting the post yesterday to post [got some kind of error code then a double posting which I finally was able to delete after several tries]. I don't know if I had the problem before then or not. I'd really like for the side bar to be a side bar at 800x600 screen resolution (since that's what my old eyes like). Right now it's on the side, but not until below (or above) the current posts.

Feeling stupid ... not that that helps anything.