Even shorter...

namespace FrameworkPath
{
    using System;
    using System.Runtime.InteropServices;

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(".NET Framework Path: {0}", RuntimeEnvironment.GetRuntimeDirectory());

            Console.Write("Press <ENTER> to exit.");
            Console.ReadLine();
        }
    }
}

Stupid me...RTFM.