Error when you open IIS Manager or configure a Web site: The XML format of the configuration file is incorrect
and is the applicationhost.config problem, then it must be ApplicationHost.config is destroyed, IIS crashes.
The solution is to restore applicationhost.config.
Check the ApplicationHost.config file in the C:\Windows\System32\inetsrv\config directory first, it is best to back up a copy
Use the AppCmd.exe Restore feature provided by IIS to recover ApplicationHost.config
Run the command prompt, type cd%windir%\system32\inetsrv, and then press Enter
Run the Appcmd list Backup command to display all available backups. Then we select a backup and run Appcmd restore backup <backup name>
Done!
Http://www.cnblogs.com/yuejin/p/3385584.html
The XML format of the IIS configuration file is incorrect applicationhost.config crash recovery workaround