checkbox click event crashing

I'm working in Excel 2010. Having a problem with the Checkbox Control (ActiveX Control) crashing when I use a different Checkbox control name than conventionally assigned. Trying to code actions based on checked or not checked.

Does the naming protocol for Checkboxes require using the "Checkbox#" convention in order to support finding it when coding. Please don't laugh I'm not very technical, so what seems obvious to most is a major blind spot for me. Thank you for your help. I'm not excited about having Checkbox 1 through 100, when a more user friendly name would help my feeble brain.

Here is an example of the exact code under two different control names. The "Checkbox1" works the "CheckboxX" does not.

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Private Sub CheckBox1_Click()

If Checkbox1.Value = True Then

    Range("P9").Select
    Selection.Copy
    Range("O9").Select
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
    :=False, Transpose:=False
    Range("O9").Select
    Application.CutCopyMode = False
    Range("O9").Select

Else

    Range("O9").Select
    ActiveCell.FormulaR1C1 = ""
    Range("O9").Select

End If

End Sub

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Private Sub CheckboxX_Click()

If Checkbox1.Value = True Then
    Range("P9").Select
    Selection.Copy
    Range("O9").Select
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
    :=False, Transpose:=False
    Range("O9").Select
    Application.CutCopyMode = False
    Range("O9").Select

Else

    Range("O9").Select
    ActiveCell.FormulaR1C1 = ""
    Range("O9").Select

End If

End Sub

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