範囲、ワークシート、ワークブックを変数として入れると、作業が簡単になります。WorksheetFunction "Transpose" を使用してデータを変更します。次のようになります。
Sub Macro2()
Dim wb1 as Workbook, wb2 as Workbook
Dim ws1 as Worksheet, ws2 as Worksheet
Dim rngSource as Range, Dim rngDest as Range, rngTemp as Range
Dim varArray() as Variant
Set wb1 = Workbooks("Original_SET_Data.xls")
Set wb2 = Workbooks("New_SET_Data.xlsx")
'To work through all sheets in Original_Set_Data.xls, you can replace this line with a "For each ws1 in wb1.Worksheets" loop and put Next at the end.
Set ws1 = wb1.Worksheets("Whatever_The_Source_Sheet_Is_Called")
Set ws2 = wb2.Worksheets("Whatever_The_Destination_Sheet_Is_Called")
'Find the Source Range & Next Available Destination Column
Set rngSource = ws1.Range("D5", ws1.Range("D60000").end(xlUp).Address)
Set rngDest = ws2.Range("IV7").End(xlToLeft).Offset(0,1)
'Loop through Source Range and Transpose Data
For each rngTemp in rngSource
'Put values from columns D to L into an array
varArray = ws1.Range(rngTemp, rngTemp.Offset(0, 8).Value)
'Transpose data - there are 9 columns D to L so we resize the range to be 9 rows high
rngDest.Resize(9,1).Value = WorksheetFunction.Transpose(varArray)
'Move to next column in new sheet
Set rngDest = rngDest.Offset(0,1)
Next
End Sub