SAPI: Application is not speaking

Please have a look at the following code

main.cpp

    #define _ATL_APARTMENT_THREADED

#include <atlbase.h>
//You may derive a class from CComModule and use it if you want to override something,
//but do not change the name of _Module
extern CComModule _Module;
#include <atlcom.h>

#include <sapi.h>
#include <iostream>

using namespace std;

int main(int argc, char* argv[])
{
    cout << "Hello" << endl;
    ISpVoice * pVoice = NULL;

    if (FAILED(::CoInitialize(NULL)))
        return FALSE;

    HRESULT hr = CoCreateInstance(CLSID_SpVoice, NULL, CLSCTX_ALL, IID_ISpVoice, (void **)&pVoice);
    if( SUCCEEDED( hr ) )
    {
        cout << "Succeeded" << endl;
        hr = pVoice->Speak(L"Hello world", 0, NULL);
        pVoice->Release();
        pVoice = NULL;
    }
    else
    {
        cout << "Not succeeded" << endl;
    }

    ::CoUninitialize();
    return TRUE;
}

When I run this code, the window opens, prints the "Hello" message. but no sound is coming out! It supposed to speak "Hello World" ! Why is this?

Following is the QT .pro settings in case it is required

Following is the QT .pro settings

#-------------------------------------------------
#
# Project created by QtCreator 2013-05-03T14:31:00
#
#-------------------------------------------------

QT       += core

QT       -= gui

TARGET = Speech
CONFIG   += console
CONFIG   -= app_bundle

TEMPLATE = app


SOURCES += main.cpp

INCLUDEPATH += "C:/Program Files/Microsoft Speech SDK 5.1/Bin"
INCLUDEPATH += "C:/Program Files/Microsoft Speech SDK 5.1/Include"



LIBS += "C:/Program Files/Microsoft Speech SDK 5.1/Lib/i386/sapi.lib"
LIBS += "C:/Program Files/Microsoft SDKs/Windows/v7.0A/Lib/User32.lib"

This issue is a driver error or application conflict. My laptop is Dell inspiron 4030 and it is the one where this issue happens. Works in my Desktop PC.