I've continued to try and narrow down the problem, and it seems to be
related to running scripts on the page being viewed.  The page I've been
using to test this out is http://www.anandtech.com/, which has script
powered banner ad near the top.  If I increase my security setting  so that
I've disabled scripts running on the page, I don't see the increase in CPU
usage after I visit the page and close Internet Explorer.  If I allow
scripts to run, I do get the increase in CPU usage after I visit the site
and close down Internet Explorer.

This leads me to speculate that it is related to how Microsoft Internet
Explorer goes about running java scripts, which leaves something still
active, even after Internet Explorer is closed, or that it is related to the
particular script on AnandTech's page somehow misbehaving and still trying
to run, even after I've closed Internet Explorer.

I'm afraid that my limited knowledge about java scripts and how browsers run
them won't let me do more than make the above wild guesses, so if anyone has
some better insights, I'd appreciate them.

John

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