Hide/Unhide Sheets based on drop down list

Dim i As Integer
Dim SheetCount As Long

SheetCount = ThisWorkbook.Worksheets.Count

If Sheets("Sheet1").Cells(1, "A").Value2 = "ALL" Then

    For i = 2 To SheetCount
        Sheets(i).Visible = xlSheetVisible
    Next i
Else

    For i = 2 To SheetCount
        If Sheets(i).Name = Sheets("Sheet1").Cells(1, "A").Value2 Then
            Sheets(i).Visible = xlSheetVisible
        Else
            Sheets(i).Visible = xlSheetHidden
        End If
    Next i

End If

Dump that into Sheet1's VBA

EDIT: Remove the target statement all together or change the range from "A1" to "A1:A2", and just add my code to the existing "Worksheet Change" code. ....I believe is the solution