Why won't my GUI destroy upon button activation?

I'm making a game that has a start menu in it. I want that GUI to disappear upon the player clicking the "Start Game" button, but it currently doesn't do anything when you click the button.

Here's my code:

local button = script.Parent
local toggled = false
local guiObj = ScreenGui 

local function onButtonActivated()
    if toggled == false then
        guiObj:Destroy()
    else
        button.Text = "Start Game"
        toggled = false
    end
end

button.Activated:Connect(onButtonActivated)

Any tips would be appreciated, thanks! :)

local button = script.Parent
local guiObj = game.StarterGui.ScreenGui

button.MouseButton1Click(
    function()
        guiObj:Destroy()
        button.Text = "Start Game"
    end
)

local button = script.Parent

local guiObj = ScreenGui 

local function onButtonActivated()
	if guiObj.Enabled == false then
		guiObj.Enabled = true
	elseif guiObj.Enabled == true then
		guiObj.Enabled = false
	end
end

button.Activated:Connect(onButtonActivated)