Facing issue with TKinter:observing "unresponsive state"

Question

Below is my code I am trying to run 3 test cases but the tkinter going to unresponsive state, I tried using threads as well but still facing the same issue and seeing one more error msg "The process cannot access the file because it is being used by another process." and I am not sure if the threads stopping after given duration or not, It seems those are not terminating. can any one check the code and please help.

my code

import threading
from tkinter import *
import time
import random
import os 
import datetime
import Test_cases

Tc =Test_cases.Test()

class Blocking():
    def __init__(self):
        self.window_main = Tk(className='Naren-App',)
        self.window_main.geometry("600x300")
        Label(self.window_main, text="Stability Tool").place(x=460, y=100, anchor="center")

        # adding a label Frame to the Main window
        self.Frame_window = LabelFrame(self.window_main, text = 'Test Cases')
        self.Frame_window.config(width=400, height=800)
        self.Frame_window.place(x=300, y=200, anchor="center")

        self.var1 = IntVar()
        self.Check_Button_1 = Checkbutton(self.Frame_window, text = "Screen_ON_OFF_Test",variable=self.var1).pack()
        self.var2 = IntVar()
        self.Check_Button_2 = Checkbutton(self.Frame_window, text = "WWAN_LPM_To_Online",variable=self.var2).pack()
        self.var3 = IntVar()
        self.Check_Button_3 = Checkbutton(self.Frame_window, text = "Get_Device_State",variable=self.var3).pack()
        Label(self.Frame_window, text="Enter Each Test Duration in Sec").pack()
        self.Duration = IntVar() # to set default value 
        self.TestDuration = Entry(self.Frame_window, textvariable=self.Duration).pack()



        #submitBtn = Button(self.Frame_window, text="submit", command=lambda:submit(Check_Button_1.get(),Check_Button_2.get(),Check_Button_3.get()))
        self.submitBtn = Button(self.Frame_window, text="submit", bg='blue',state=NORMAL,command=self.submit)
        self.submitBtn.pack()


        #stability 
        self.Frame_window = LabelFrame(self.window_main, text = 'Stability')
        self.Frame_window.config(width=400, height=800)
        self.Frame_window.place(x=600, y=200, anchor="center")

        self.var4 = IntVar()
        self.Test_Name_Check_button = Checkbutton(self.Frame_window, text = "Test_Name",variable=self.var4).pack()
        self.var5 = IntVar()
        self.NumberOf_Iterations_Check_button = Checkbutton(self.Frame_window, text = "NumberOf_Iterations",variable=self.var5).pack()
        self.var6 = IntVar()
        self.NumberOf_Hours_Check_button = Checkbutton(self.Frame_window, text = "NumberOf_Hours",variable=self.var6).pack()

        self.submitBtn2 = Button(self.Frame_window, text="submit", bg='blue', state =DISABLED,command=self.submit)
        self.submitBtn2.pack()
        self.window_main.mainloop()
    
    def submit(self):
            print("var1: %d,\n var2: %d,\nvar3: %d,\nDuration: %d" % (self.var1.get(), self.var2.get() , self.var3.get(), self.Duration.get()))
            TestDuration = int(self.Duration.get())
            print("Test Duration2:", TestDuration)
            Tc.Duration = TestDuration
            print("Passing Duration:", Tc.Duration)
            self.submitBtn['bg']='blue'
            self.submitBtn['state']=DISABLED
            if self.var1.get() == 1 : 
                    print("Starting Screen on off \n")
                    print("Screen On OFF Test Will run For:",TestDuration ,"sec \n")
                    T1=threading.Thread(target=Tc.Screen_ON_OFF()).start()
                    time.sleep(TestDuration+5)
                    #T1.join()
            if self.var2.get() == 1 :
                    print("Starting LPM to Online \n")
                    print("LPM to Online Test Will run For:",TestDuration ,"sec \n")
                    T2=threading.Thread(target=Tc.LPM_To_Online()).start()
                    time.sleep(TestDuration+5)
            if self.var3.get() == 1 :
                    print("Getting device state \n")
                    print("Getting device statet Will run For:",TestDuration ,"sec \n")
                    T1=threading.Thread(target=Tc.Get_Device_State()).start()
                    time.sleep(TestDuration+5)
            return Label(self.window_main, text="Submitted!").pack()


def main():
    block = Blocking()
   
if __name__ == '__main__':
    main()