检查是否安装声卡 
     利用VB检查声卡,十分简单.参见下例:
>>步骤1----建立新工程,在窗体上放置一个CommandButton按钮.
>>步骤2----编写下述代码:

Private Declare Function waveOutGetNumDevs Lib "winmm.dll" _
    () As Long

Private sub Command1_Click()
    Dim nReturnValue as long
    nReturnValue = waveOutGetNumDevs()
    if nReturnValu then
        MsgBox "检测到声卡"
    Else
        MsgBox "没有检测到声卡"
    Endif
End Sub