I got the same problem like here Could not load file or assembly 'Microsoft.VisualStudio.Web.PageInspector.Loader but not on my development machine but on hosting server.
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\web.config C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\web.config
I was able to fix it by adding below code to my web.config
<compilation targetFramework="4.5">
<assemblies>
<remove assembly="Microsoft.VisualStudio.Web.PageInspector.Loader,
Version=1.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
</assemblies>
</compilation>
or by removing reference to this assembly from web.config files in framework directories.
I never installed VS there and i never had PageInspector installed there. Any idea why those configs reference them?