If you only used MSIE, it's a mystery. It rather seems as if you copied the text from some other source into the post editor. The editor should work equally good in any browser.
What you have in that post is a lot of
<font size="3"></font><font size="3"></font> etc.
Some of the font tags must must miss the end tag.
You could open that post in the (X)HTML editor of WordPress and clean out all font tags, of course, but I think an easier way would be to copy content.
I suggest the following route:
1. Copy the post text from your webpage into a plain text editor. If you use Windows, Notepad is good enough.
( Check that you have no HTML tags, just the text. )
2. Delete the post from your Dashboard Manage Posts.
3. Go to Write/Post and copy the plain test from your text editor. Insert linefeeds if nescassary.
4. Publish your redesigned post.