How do you open UserForm1 with a checkbox?

Hello All!

I'm having a bit of trouble getting my UserForm1 to appear when I check an existing checkbox on my worksheet. Right now the Checkbox is used to hide and unhide 3 rows of cells. I would like to modify that checkbox so that when clicked it shows the three rows as well as opens my user form. The code that I am attempting to weld together is:

Sub OpenUserForm1()
frmUserForm1.Show
End Sub
Sub CheckBox7_Click()
If Rows("45:47").RowHeight = 0 Then
     Rows("45:47").Hidden = False
    Else
     Rows("45:47").Hidden = True
    End If
    End Sub

Please give me a hand if you can. As always, any help, advice, opinions, etc. are appreciated.

Thanks!