Hmmm, one additional thing you can try is to use the IE7 reset. There have been some cases where this also helped repair someone's settings.

This is described in this blog: http://blogs.msdn.com/ie/archive/2006/06/12/628499.aspx

From IE7, go to the Tools Menu, Internet Options, Advanced Tab, and click on the Reset button near the bottom.

That may also help restore your registry settings.

- Michael