Show second window using classes

[iFunKtion]

Thank you once again Yoriz, this now works, I have stripped it down to the basics of what the question was addressing and I have also formatted the code in what appears to me to be a more standard pythonic format, please correct me if I have that wrong. This is what I have that now does exactly what I was after, I have set geometry the same as in my project and as the sub_windows will all be the same size and location, geometry is defined in init definition of the Form class.

#!/usr/bin/python3
# -*- coding: utf-8 -*-

"""
Qt4 example to embed
dialog box within window
"""

from PyQt4 import QtGui, QtCore

class Form(QtGui.QWidget):
    """Menu window"""
    def __init__(self, parent=None):
        super(Form, self).__init__()
        self.setGeometry(1000, 200, 400, 500)


class Window(QtGui.QMainWindow):
    """Main Window"""
    def __init__(self, parent=None):
        super(Window, self).__init__()
        self.setGeometry(50, 50, 1600, 900)
        self.new_window = Form(self)
        self.show() 
        self.dialog = Form(self)
        self.dialog.show()


         
def main():
    app = QtGui.QApplication(sys.argv)
    main_window = Window()
    sys.exit(app.exec_())    
 
if __name__ == "__main__":
    main()

Kind regards
iFunk