<p>I'm using IE8 and have similar problems.  I have to update the screen in "compatibility view" (the little green button to the right of where the url's are displayed).</p>

<p>Sometimes it will replace all MathJax entries with [Math Processing Error].   When that happens, I close down IE8 and restart it, and try again.</p>

<p>Also, under Tools, under Compatibility View Settings, I have experimented with adding/deleting certain websites that show up as "compatible" by default.   Sometimes it helps, sometimes not.</p>
