many possibly reasons – invalid html code is just one of them – and fixing it depends on what is wrong.
for instance, try to use the http://validator.w3.org/ to get hints if there are unmatched or missing html tags.
these could be in the content of the latest posts, or in the templates if you edited them recently;
is the problem on the front page only or also in static pages or single posts?
if you post a link to your site, someone might help checking…
I went back to my site later & the sidebar had moved itself back again. I think it had to do with my Adsense kicking in & starting the ads on my site. But thanks for the quick response anyway!
