I has getting the following error every time I build the my page or project in Visual Studio Express 2012. Error 78 (0): error CS1703: An assembly with the same identity 'System.Web.Extensions, Version=3.5.0.0, Culture=neutral, has already been imported. To fix it I goggled all over eventually I figured this out: In Solution Explorer right click on the root of the project then click "Property Pages" (or Shift+F4) Then it will display something like this: Select the assembly that is giving problems and then click "Remove" ;) Problems solved.
Just some opinions and things I have committed to virtual prosperity just in case UGAF