Read multiple text files into a Spreadsheet

Try this.

Sub ReplaceCR()
Dim C As Range
Dim FirstAddress As String

With ActiveSheet.Range("A1").CurrentRegion
    Set C = .Find(Chr(13), , xlValues, xlPart)
    If Not C Is Nothing Then
        FirstAddress = C.Address
        Do
            C.Value = Replace(C.Value, Chr(13), ",")
            Set C = .FindNext(C)
        Loop While Not C Is Nothing And C.Address <> FirstAddress

    End If
End With

End Sub