One day, when my VPC was closed unexpected, the IIS can’t restart and throw error:

The Windows Process Activation Service encountered an error trying to read configuration data from file ‘\\?\C:\Windows\system32\inetsrv\config\applicationHost.config’, line number ‘0’. The error message is: ‘Configuration file is not well-formed XML’

Luckily IIS makes a backup each time you make a change. All those versions are stored in the folder C:\inetpub\history\. All you have to do is to copy a former applicationHost.config file into the C:\Windows\System32\inetsrv\config\ working directory.