' FindWindow函数声明
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, _
ByVal lpWindowName As String _
) As Long
' PostMessage函数声明
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" _
(ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lParam As Any _
) As Long
'关闭程序需要的常量
Const WM_CLOSE = &H10

Private Sub Command1_Click()
Dim winHwnd As Long
Dim RetVal As Long
winHwnd = FindWindow(vbNullString, "编程论坛-『VB6论坛』- Microsoft Internet Explorer")
Debug.Print winHwnd
If winHwnd <> 0 Then
RetVal = PostMessage(winHwnd, WM_CLOSE, 0&, 0&)
If RetVal = 0 Then
MsgBox "关闭浏览器出错！"
End If
Else
MsgBox "浏览器器没有运行。"
End If
End Sub

那就用Timer控件,要不就直接结束IE进程更过瘾