I\'m running Windows 7 Ultimate (64 bit) using Visual Studio 2010 RC. I recently decided to have VS run/debug my apps on IIS rather than the dev server that comes with it. <
Sweet Jesus. I tried all of the above things (but found my settings identical). YET ANOTHER SOLUTION if you are having issues:
http://support.microsoft.com/kb/980368
Try installing this KB for your system. If you are seeing 404s it might be because you don't have this update -- and the isapi module just isn't getting found and there's not a lot you can do about that without this!