public static Object GetReferenceFromClass(string AssemblyName, string ClassName, object[] args)

        {

            Assembly assembly = Assembly.LoadFrom(AssemblyName);

            foreach (Type type in assembly.GetTypes())

            {

                if (type.IsClass == true)

                {

                    if (type.FullName.EndsWith("." + ClassName))

                    {

                        ConstructorInfo[] con = type.GetConstructors();

                        foreach (ConstructorInfo construtor in con)

                        {

                            if (construtor.GetParameters().Length == args.Length)

                            {

                                return construtor.Invoke(args);

                            }

                        }

                    }

                }

            }

            throw (new System.Exception("could not create instanace----->" + ClassName));

        }

Thank you

 If (cCurrForm.GetType.Name <> pForm) Then
   cCurrForm.Close
   cCurrForm = DirectCast(Activator.CreateInstance(Assembly.GetExecutingAssembly.GetType(pForm)), Form) 
End If

cCurrForm  - must be base class for pForm  and previos form. In common case, it may be System.Windows.Form.

But if you want more, than simple showing, you should or use a casting to needed form, or use base class or interface.