Configuring IIS site to use HTTPS
OK,
Based on your Fiddler it looks like you might actually have an Apache box listening on port 443. It can be easy to overlook, especially if it was bundled with another piece of software. Run the following command, see if port 443 is being listened to and what program is listening on it. This should help us figure out if IIS is indeed controlling that port of if some other program is.
netstat -aon | findstr 0.0:443