[solved]Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies.

Couldnot load file or assembly 'System.Web.WebPages.Razor,
Version=3.0.0.0,Culture=neutral, 
PublicKeyToken=31bf3856ad364e35' or one of its
 dependencies.The located assembly's manifest definition 
does not match the assemblyreference.
 (Exception from HRESULT: 0x80131040)

Description: Anunhandled exception occurred during the execution of the current web request.Please review the stack trace for more information about the error and where itoriginated in the code. 

Exception Details: System.IO.FileLoadException:Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0,Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies.The located assembly's manifest definition does not match the assemblyreference. (Exception from HRESULT: 0x80131040)

I got this error that the web.config was referencing System.Web.WebPages.Razor,Version=2.0.0.0. Later I changed it to System.Web.WebPages.Razor, Version=3.0.0.0.

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages.Razor" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="3.0.0.0" />      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="DotNetOpenAuth.AspNet" publicKeyToken="2780ccd10d57b246" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.3.0.0" newVersion="4.3.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="DotNetOpenAuth.Core" publicKeyToken="2780ccd10d57b246" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-4.3.0.0" newVersion="4.3.0.0" />
      </dependentAssembly>
      <dependentAssembly> 
</assemblyBinding>

If you still have trouble then I recommended you to update the pakage.Run the following command in the Package Manager Console. 

PM> Update-Package