How long did this take me to figure out? It was hours not minutes.
After deleting the default IIS website and then wanting to re-enable this I struggled to reinstall IIS on a Windows 2008R2 server.
Each and every time (yes I did it a few times) I un-installed the IIS Role and re-installed (even after manually deleting the inetpub directory) I would get my old server details and no Default website back.
This is because the config is backed up outside of IIS by the Windows Process Activation Service.
I finally found this which gave me a clue to the issue. Phew.
I had to reboot after IIS role was removed before I could un-install Windows Process Activation Service.
I also had to manually add Windows Process Activation Service back in after IIS installation had finished.
Hope you find this quicker that I did.