Как сделать checkbox по умолчанию отмеченным в tKinter

хочу сделать чтобы по умолчанию было установлено несколько checkbox. пробовал через offvalue и onvalue. но не прошло.

Вот код:

from tkinter import *
import os


win = Tk()
win.title("win")
win.geometry("300x265")
win["bg"] = "gray6"



# Browsers:


def Install():
    if (Chrome.get()):
        os.system('Start Chrome.exe')
    if (Yandex.get()):
        os.system('Start Yandex.exe')
    if (FireFox.get()):
        os.system('Start FireFox.exe')
    if (winRAR.get()):
        os.system('Start winRAR.exe')
    if (Zip.get()):
        os.system('Start 7z.exe')
    if (MicrosoftOffice.get()):
        os.system('Start MicrosoftOffice.exe')
    if (LibreOffice.get()):
        os.system('Start LibreOffice.exe')
    if (uTorrent.get()):
        os.system('Start uTorrent.exe')
    if (qBitTorrent.get()):
        os.system('Start qbittorrent.exe')
    if (DriverBooster.get()):
        os.system('Start DriverBooster.exe')
    if (UninstallTool.get()):
        os.system('Start UninstallTool.exe')
    if (Notepad.get()):
        os.system('Start Notepad.exe')
    if (Picasa.get()):
        os.system('Start Picasa.exe')
    if (MiniBin.get()):
        os.system('Start MiniBin.exe')
    if (EarTrumpet.get()):
        os.system('Start EarTrumpet.exe')
    if (Everything.get()):
        os.system('Start Everything.exe')
    if (Lightshot.get()):
        os.system('Start Lightshot.exe')
    if (Flux.get()):
        os.system('Start Flux.exe')
    if (Battery.get()):
        os.system('Start Battery.exe')
    if (Tach_B590.get()):
        os.system('Start Tach_B590.exe')



Browser = Label(win,
                text='Browser',
                bg="gray6",
                fg="red")\
                .place(x=1, y=1)

Chrome = BooleanVar()
ChromeC = Checkbutton(win,
                     text='Chrome', 
                     variable=Chrome, 
                     bg="gray6", 
                     fg="green3",  
                     activebackground="gray6", 
                     activeforeground="green3", 
                     selectcolor="gray6", 
                     )\
                     .place(x=10, y=20) 

Yandex = BooleanVar()
YandexC = Checkbutton(win,
                     text='Yandex', 
                     variable=Yandex, 
                     bg="gray6", 
                     fg="green3",  
                     activebackground="gray6", 
                     activeforeground="green3", 
                     selectcolor="gray6",
                     )\
                     .place(x=10, y=39)

FireFox = BooleanVar()
FireFoxC = Checkbutton(win,
                      text='FireFox',
                      variable=FireFox,
                      bg="gray6",
                      fg="green3",
                      activebackground="gray6",
                      activeforeground="green3",
                      selectcolor="gray6",
                      )\
                      .place(x=10, y=58)


# Archiver:



Archiver = Label(win,
                 text='Archiver',
                 bg="gray6",
                 fg="red")\
                 .place(x=1, y=77)

winRAR = BooleanVar()
winRARC = Checkbutton(win,
                     text='winRAR',
                     variable=winRAR,
                     bg="gray6",
                     fg="green3", 
                     activebackground="gray6",
                     activeforeground="green3",
                     selectcolor="gray6",
                     )\
                     .place(x=10, y=96)

Zip = BooleanVar()
ZipC = Checkbutton(win,
                  text='7zip',
                  variable=Zip,
                  bg="gray6",
                  fg="green3", 
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=10, y=115)


# Office:



Office = Label(win,
               text='Office',
               bg="gray6",
               fg="red")\
               .place(x=1, y=134)

MicrosoftOffice = BooleanVar()
MicrosoftOfficeC = Checkbutton(win,
                              text='MicrosoftOffice',
                              variable=MicrosoftOffice,
                              bg="gray6",
                              fg="green3",
                              activebackground="gray6",
                              activeforeground="green3",
                              selectcolor="gray6",
                              )\
                              .place(x=10, y=153)

LibreOffice = BooleanVar()
LibreOfficeC = Checkbutton(win,
                          text='LibreOffice',
                          variable=LibreOffice,
                          bg="gray6",
                          fg="green3", 
                          activebackground="gray6",
                          activeforeground="green3",
                          selectcolor="gray6",
                          )\
                          .place(x=10, y=172)


# Torrent:



TorrentC = Label(win,
                text='Torrent',
                bg="gray6",
                fg="red")\
                .place(x=1, y=191)

uTorrent = BooleanVar()
uTorrentC = Checkbutton(win,
                       text='uTorrent',
                       variable=uTorrent,
                       bg="gray6",
                       fg="green3",
                       activebackground="gray6",
                       activeforeground="green3",
                       selectcolor="gray6",
                       )\
                       .place(x=10, y=210)

qBitTorrent = BooleanVar()
qBitTorrentC = Checkbutton(win,
                          text='qBitTorrent',
                          variable=qBitTorrent,
                          bg="gray6",
                          fg="green3",
                          activebackground="gray6",
                          activeforeground="green3",
                          selectcolor="gray6",
                          )\
                          .place(x=10, y=229)





DriverBooster = BooleanVar()
DriverBoosterC = Checkbutton(win,
                  text='DriverBooster',
                  variable=DriverBooster,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=1)


UninstallTool = BooleanVar()
UninstallToolC = Checkbutton(win,
                  text='UninstallTool',
                  variable=UninstallTool,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=20)


Notepad = BooleanVar()
NotepadC = Checkbutton(win,
                  text='Notepad++',
                  variable=Notepad,
                  bg="gray6",
                  fg="cyan2", 
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=39)


Picasa = BooleanVar()
PicasaC = Checkbutton(win,
                  text='Picasa',
                  variable=Picasa,
                  bg="gray6",
                  fg="cyan2", 
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=58)


MiniBin = BooleanVar()
MiniBinC = Checkbutton(win,
                  text='MiniBin',
                  variable=MiniBin,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=77)


EarTrumpet = BooleanVar()
EarTrumpetC = Checkbutton(win,
                  text='EarTrumpet',
                  variable=EarTrumpet,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=96)


Everything = BooleanVar()
EverythingC = Checkbutton(win,
                  text='Everything',
                  variable=Everything,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=115)


Lightshot = BooleanVar()
LightshotC = Checkbutton(win,
                  text='Lightshot',
                  variable=Lightshot,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=134)


Flux = BooleanVar()
FluxC = Checkbutton(win,
                  text='Flux',
                  variable=Flux,
                  bg="gray6",
                  fg="cyan2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=153)


# for NoteBook:


Battery = BooleanVar()
BatteryC = Checkbutton(win,
                  text='Battery',
                  variable=Battery,
                  bg="gray6",
                  fg="seagreen2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=191)


Tach_B590 = BooleanVar()
Tach_B590C = Checkbutton(win,
                  text='Tach_B590',
                  variable=Tach_B590,
                  bg="gray6",
                  fg="seagreen2",
                  activebackground="gray6",
                  activeforeground="green3",
                  selectcolor="gray6",
                  )\
                  .place(x=150, y=210)




Install = Button(win,
                 text='Install',
                 bg="gray6",
                 fg="khaki1",
                 bd="0",
                 activebackground="gray6",
                 activeforeground="lawn green",
                 width="4",
                 height="1",
                 command=Install)\
                 .place(x=250, y=237)

win.mainloop()