Unmute Volume In Vb2008?

I was creating a OS with vs 2008 and I made some easter eggs where if a key is pressed, it will show a full screen image of a RSoD. In the form's code, there is a code to mute all the volume I got in the internet:

Public Class Form6
Private Const APPCOMMAND_VOLUME_MUTE As Integer = &H80000
Private Const WM_APPCOMMAND As Integer = &H319
Declare Function SendMessageW Lib "user32.dll" (ByVal hWnd As IntPtr, ByVal Msg As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr

[Code]...

And pressing the space key will bring it back to my desktop in the own-made OS.There are sounds I coded in it. But as the code above mutes the computer, I must unmute by my self. Can anyone give me the code to unmute??? Googling it up does not work.