This is a bit like fishing in the dark, but I guess it would be something like
Public Sub ProcessData()
Const TEST_COLUMN As String = "A" '<=== change to suit
Dim i As Long
Dim iLastRow As Long
Const delim As String = ", " 'change to suit
With ActiveSheet
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
iLastRow = .Cells(.Rows.Count, TEST_COLUMN).End(xlUp).Row
For i = 2 To iLastRow
.Cells(i, "F").Value = .Cells(i, "A") & delim & _
.Cells(i, "B") & delim & _
.Cells(i, "C") & delim & _
.Cells(i, "D") & delim & _
.Cells(i, "E")
Next I
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
End With
End Sub