IEの既存のプロセスの新規ウィンドウで開く。

WWW_OpenURLNewWindow.VBS {ファイル|URL}

URL=WScript.Arguments.Item(0)
Set Application=CreateObject("Excel.Application")
Application.DisplayAlerts=False
channelNumber=Application.DDEInitiate("IExplore","WWW_OpenURLNewWindow")
Application.DisplayAlerts=True
If TypeName(channelNumber)="Error" Then
  CreateObject("WScript.Shell").Run "IExplore.exe " & """" & URL & """"
Else
  Application.DDEExecute channelNumber,"""" & URL & """,,-1,0,,,,"
  Application.DDETerminate channelNumber
End If

これは、WWW_OpenURLで、第3パラメタのWindowIDを-1(最新)でなく、0(新規)を指定しても同じです。

WWW_OpenURL2.VBS {ファイル|URL}

URL=WScript.Arguments.Item(0)
Set Application=CreateObject("Excel.Application")
Application.DisplayAlerts=False
channelNumber=Application.DDEInitiate("IExplore","WWW_OpenURL")
Application.DisplayAlerts=True
If TypeName(channelNumber)="Error" Then
  CreateObject("WScript.Shell").Run "IExplore.exe " & """" & URL & """"
Else
  Application.DDEExecute channelNumber,"""" & URL & """,,0,,,,,"
  Application.DDETerminate channelNumber
End If