IIS Express Hangs

I'm using VS2010 Express with SP1 on XP Pro SP3.  I have a web development site on a local drive that was running fine under IIS Express a few days ago.  Now when I launch under IIS Express, IIS Express goes up to 50% CPU usage and doesn't come down, eventually freezing the machine for at least several minutes (at which point I do a hard PC restart).    The site works fine under the VS Development Server (Cassini).  Under IIS Express the page call is

http://localhost:4306/mypage

I made two changes recently that might have affected things.  1) I made a copy of the site for operations testing and got it to run under IIS 5.1.  Then I pointed IIS 5.1 at the development site, and got it to run; works fine.  2)  I renamed the folder that the development site was in, and then could not figure out how to get VS2010 Express to recognize it on the start page; but I got past that.

I tried uninstalling IIS Express and reinstalling, no joy.  

I tried looking at the IISExpress folder config files xml however I can't find documentation to tell me what I might do with them.

I need IIS Express because I've got extensive javascript and REALLY don't want to go back to Cassini for JS debug.

Any suggestions on how to get IIS Express back up and running properly on my development site would be appreciated.

Thanks!