Activate an open workbook

Greetings to all. The following macro opens the workbook "orderform". I need to change it so that it activates "orderform" since it is already open. Its probably very simple, but beyond me. Thanks!

Dim wbMain As Workbook
Dim wbOther As Workbook
Set wbOther = ActiveWorkbook
Range("C1:Bh1").Select
Selection.Copy
Set wbMain = Workbooks.Open("C:\Order Entry\orderform.XLS")

Thanks so much!