Option Explicit

Private Sub Timer1_Timer()
FlashWindow Me.hwnd,True '调用flashwindow函数是窗体标题栏闪烁
Beep '使计算机的扬声器发出响声
End Sub

Option Explicit

Public Declare Function FlashWindow Lib "user32" (ByVal hwnd As Long,ByVal bInvert As Long) As Long
'函数原型： Declare Function FlashWindow Lib "user32" Alias "FlashWindow" (ByVal hwnd As Long,ByVal bInvert As Long) As Long
'函数说明： 闪烁显示指定窗口。这意味着窗口的标题和说明文字会发生变化，似乎从活动切换到非活动状态、或反向切换。通常对不活动的窗口应用这个函数，引起用户的注意

FlashWindow ：http://baike.baidu.com/view/1906929.htm