If you want to select a single cell and run the macro, this untested sub might work
Sub UsedToBe_Worksheet_Change()
Dim r As Range
If Not TypeOf Selection Is Range Then Exit Sub
If Selection.Cells.Count > 1 Then Exit Sub
If Intersect(Selection, Columns(1)) Is Nothing Then Exit Sub
Set r = Selection
Application.EnableEvents = False
On Error Resume Next
With r.Offset(, 1)
.Formula = "=VLookup(" & r.Address & ", Data, 5, False)"
.Value = .Value
End With
With r.Offset(, 2) 'Column C
.Formula = "=VLookup(" & r.Address & ", Data, 6, False)"
.Value = .Value
End With
On Error GoTo 0
'get rid of NA
If WorksheetFunction.IsNA(r.Offset(, 1)) Then r.Offset(, 1).ClearContents
If WorksheetFunction.IsNA(r.Offset(, 2)) Then r.Offset(, 2).ClearContents
Application.EnableEvents = True
End Sub
There are other ways, but this one seems to be truest to your code
Paul