Configuration section 'appSettings' cannot be read because it is missing a section declaration

I was clearing ASP.NET Temporary Internet files and I accidentally deleted some files in framework folde. I have done it for 4.0. Now Visual Studio 2013 is not opening. When trying to run application set to 32 bit in app pool, an error in web.config appSettings, though appSettings was working normally before the deleting incident, appears.I don't know what went wrong and how to fix this. I am using Windows Server 2016. I tried with iis turn on or off in windows features. What we can do to restore.

IIS Error:

HTTP Error 500.19 - Internal Server Error

The requested page cannot be accessed because the related configuration data for the page is invalid.

Error Code

0x80070032

Config Error

The configuration section 'appSettings' cannot be read because it is missing a section declaration

the config file:

The problem is with the Visual Studio and IIS? Try to repair the installation of Visual Studio from Windows Control Panel. About IIS - there is a post regarding this - http://kb.act.com/app/answers/detail/a_id/22001/~/how-to-uninstall-and-reinstall-asp.net-from-the-command-prompt

cd %windir%\Microsoft.NET\Framework64\v4.0.30319
aspnet_regiis.exe –i

Maybe there are some problems with the .Net Framework itself, Microsoft made a tool to fix some common problems - https://www.microsoft.com/en-us/download/details.aspx?id=30135

If the repair of Visual Studio did not help, try to uninstall it, and the install again. There is also an old (and archived) program to help uninstalling Visual Studio - https://github.com/Microsoft/VisualStudioUninstaller/releases

I hope this helps!