How to copy the contents of the active sheet to a new workbook?

Don't use Copy method at all if you're only concerned with saving the Values.

Sub new_workbook()
Dim wbMe As Workbook: Set wbMe = ThisWorkbook
Dim ws As Worksheet: Set ws = wbMe.ActiveSheet
Dim ExtBk As Workbook

Set ExtBk = Workbooks.Add
ExtBk.SaveAs Filename:=wbMe.Path & "\output.xls"

ExtBk.Worksheets("Sheet1").Range("A:N").Value = ws.Range("A:N").Value

Application.DisplayAlerts = False
ExtBk.Save
Application.DisplayAlerts = True

End Sub

Note: this will fail (and so will your code, previously) if your ThisWorkbook is unsaved.

I made it work:

Sub cp2NewWb()
    Dim ExtFile As String
    ExtFile = ThisWorkbook.Path & "output.xls"
    Workbooks.Add.SaveAs Filename:="output.xls"

    Windows("test1.xlsm").Activate
    Range("A1:AA100").Copy
    Windows("output.xls").Activate
    Range("A1").Select
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
    :=False, Transpose:=False
    Worksheets(Worksheets.Count).Columns("A:AA").EntireColumn.AutoFit
    Range("A1").Select

    Windows("test1.xlsm").Activate
    Application.CutCopyMode = False
    Range("A1").Select
End Sub

I need to do it between activating windows or it doesn't work.