Не работает переход между окнами в PyQt5

НИКОГДА НЕ ИЗМЕНЯЙТЕ код, сгенерированный Qt Designer, НИКОГДА.
Создайте другой класс, который наследуется от соответствующего виджета, и используйте созданный класс для его заполнения.

Qt Main Window Framework

Всегда запускайте приложение в консоли/CMD/терминале и вы пулучите реальную ошибку.

import sys
from PyQt5.QtWidgets import QApplication, QLabel, QMainWindow, \
    QPushButton, QTextEdit
from PyQt5.QtGui import QPixmap, QIcon
from PyQt5 import QtCore, QtGui, QtWidgets


# +++ vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(1125, 807)
        MainWindow.setWindowIcon(QIcon('resource/img/logo2.png'))
        MainWindow.setStyleSheet("background-color: rgb(18, 18, 18);")
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(350, 180, 441, 91))
        self.label.setText("")
        self.label.setPixmap(QtGui.QPixmap("boy.jpg"))
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(80, 60, 41, 51))
        self.label_2.setText("")
        self.label_2.setPixmap(QtGui.QPixmap("Ok.png"))
        self.label_2.setScaledContents(True)
        self.label_2.setObjectName("label_2")
        
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(480, 320, 191, 61))
        self.pushButton.setFlat(True)
        self.pushButton.setObjectName("pushButton")
        self.pushButton.setStyleSheet("background-color: rgb(55, 55, 55);")
        
        MainWindow.setCentralWidget(self.centralwidget)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "Приложение EpicGames"))
        self.pushButton.setText(_translate("MainWindow", "PushButton"))


class Window2(QMainWindow, Ui_MainWindow):
    def __init__(self):
        super().__init__()    
        self.setupUi(self)
        
        self.label.setScaledContents(True)
# +++ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        

class Window(QMainWindow):
    def __init__(self):
        super(Window, self).__init__()

        self.pushButton = None
        self.label_2 = None
        self.label = None
        self.centralwidget = None
        self.setWindowTitle("Приложение EpicGames")
        self.setWindowIcon(QIcon('resource/img/logo2.png'))
        self.setGeometry(525, 162, 1125, 807)
        self.setStyleSheet('background-color: rgb(18, 18, 18);')
        self.main_text = QLabel(self)
        self.main_text.setPixmap(QPixmap("logo.png"))
        self.main_text.setScaledContents(True)
        self.main_text.setGeometry(80, 60, 41, 51)
        self.magazin = QPushButton(self)
        self.magazin.setFlat(True)
        self.magazin.setGeometry(15, 140, 162, 50)
        self.magazin.setStyleSheet("""
                QPushButton:hover { background-image: url(resource/img/mag1.jpg) }
                QPushButton:!hover { background-image: url(resource/img/mag0.png) }
                QPushButton:pressed { background-image: url(resource/img/mag2.jpg) }
                """)
        self.bibl = QPushButton(self)
        self.bibl.setFlat(True)
        self.bibl.setGeometry(15, 192, 162, 60)
        self.bibl.setStyleSheet("""
                QPushButton:hover { background-image: url(resource/img/bibl1.png) }
                QPushButton:!hover { background-image: url(resource/img/bibl0.png) }
                QPushButton:pressed { background-image: url(resource/img/bibl2.png) }
                """)
        self.un = QPushButton(self)
        self.un.setFlat(True)
        self.un.setGeometry(15, 255, 162, 55)
        self.un.setStyleSheet("""
                    QPushButton:hover { background-image: url(resource/img/un1.png) }
                    QPushButton:!hover { background-image: url(resource/img/un0.png) }
                    QPushButton:pressed { background-image: url(resource/img/un2.png) }
                    """)
        self.poisk = QTextEdit(self)
        self.poisk.setGeometry(210, 60, 181, 31)
        self.poisk.setPlaceholderText("Поиск")
        self.poisk.setStyleSheet("background-color: rgb(84, 84, 84);\n"
                                 "color: rgb(255, 255, 255);")
        self.nov = QLabel(self)
        self.nov.setGeometry(470, 70, 61, 16)
        self.nov.setStyleSheet("color: rgb(255, 255, 255);")
        self.nov.setText("Новости >")
        self.ic = QPushButton(self)
        self.ic.setFlat(True)

        self.ic.setGeometry(1000, 60, 42, 42)
        self.ic.setStyleSheet("""
                       QPushButton:hover { background-image: url(resource/img/ic1.png) }
                       QPushButton:!hover { background-image: url(resource/img/ic0.png) }
                       QPushButton:pressed { background-image: url(resource/img/ic2.png) }
                       """)
        self.raspr = QPushButton(self)
        self.raspr.setGeometry(220, 140, 672, 376)
        self.raspr.setStyleSheet("border-image: url(resource/img/123.png) stretch;")
        self.de = QPushButton(self)
        self.de.setGeometry(920, 140, 167, 50)
        self.de.setFlat(True)
        self.de.setStyleSheet("""
                          QPushButton:hover { background-image: url(resource/img/iiic1.png) }
                          QPushButton:!hover { background-image: url(resource/img/iiic0.png) }
                          QPushButton:pressed { background-image: url(resource/img/iiic1.png) }
                          """)
        self.gov = QPushButton(self)
        self.gov.setGeometry(220, 500, 866, 287)
        self.gov.setFlat(True)
        self.gov.setStyleSheet("border-image: url(boy.jpg) stretch;")
        self.gov.clicked.connect(self.err)

# +++ vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    def err(self):
        self.window2 = Window2()                                        # !!! 
        self.window2.show()                                             # !!!       
# +++ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    

if __name__ == "__main__":
    app = QApplication(sys.argv)
    w = Window()
    w.show()
    sys.exit(app.exec_())