If you want to dynamically want to load a form and you only know the classname then the following snippet may be of use:

Type t = Type.GetType("ConsoleApplication1.Form1");
if (t != null)
{
    System.Windows.Forms.Form f = (System.Windows.Forms.Form) Activator.CreateInstance(t);
    f.ShowDialog();
}

Now, if you'd want to load the form from a different assembly, let's say, some library assembly with forms, then you need to specifiy an AssemblyQualifiedName.

Like:

Type t = Type.GetType("ClassLibrary1.Form1, ClassLibrary1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null");
if (t != null)
{
    System.Windows.Forms.Form f = (System.Windows.Forms.Form)Activator.CreateInstance(t);
    f.ShowDialog();
}

This will dynamically load the form and show it. So no compiletime binding needs to be done.