Using this function you can remove a window's titlebar, you first need to find the HWND of the window( using FindWindow or FindWindowEx API), then you just call this function and it will remove the titlebar.

    

    Public Shared Function RemoveTitleBar(ByVal hwnd As IntPtr) As Boolean

        Dim style As Long = GetWindowLong(hwnd, (-16))

        style += &H800000 Or &HC00000

        Return SetWindowLong(hwnd, (-16), style)

    End Function



'APIS

<llImport("user32.dll")> _

    Public Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer, ByVal dwNewLong As IntPtr) As Integer

    End Function

<llImport("user32.dll", SetLastError:=True)> _

    Public Shared Function GetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer) As Integer

    End Function