Problem changing window settings

    
//-------------------------------------------------------------------------------------------------

// CWindow::SetFullscreenMode()

//

// Description: 

//		Switches the window to fullscreen mode.

//

// Returns: 

//		1 on success, 0 on failure.

//-------------------------------------------------------------------------------------------------

int CWindow::SetFullscreenMode()
{
	if (!m_bFullscreen)
	{
		// Switch to fullscreen mode

		DEVMODE dmScreenSettings;
		ZeroMemory(&dmScreenSettings,     sizeof(dmScreenSettings));
		dmScreenSettings.dmSize			= sizeof(dmScreenSettings);
		dmScreenSettings.dmBitsPerPel	= 32;
		dmScreenSettings.dmPelsWidth	= 800;
		dmScreenSettings.dmPelsHeight	= 600;
		dmScreenSettings.dmFields		= DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
		
		if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
			return(0);

		// Change the window style

		m_dwStyle = WS_POPUP | WS_VISIBLE | WS_CLIPCHILDREN | WS_CLIPSIBLINGS;

		// Set the new window style

		SetWindowLong(m_hWnd, GWL_STYLE, m_dwStyle);

		// Change the size of the window

		if (!SetWindowPos(m_hWnd, HWND_TOP, 0, 0, 800, 600, NULL))
			return(0);

		// Display the widow

		ShowWindow(m_hWnd, SW_SHOWNORMAL);

		// Hide the cursor

		ShowCursor(FALSE);

		// Update the Fullscreen flag

		m_bFullscreen = TRUE;
	}
	
	return(1);
}

//-------------------------------------------------------------------------------------------------

// CWindow::SetWindowedMode()

// 

// Description:

//		Switches the window to windowed mode.

//

// Returns:

//		Returns 1 on success, 0 on failure

//-------------------------------------------------------------------------------------------------

int CWindow::SetWindowedMode()
{
	if (m_bFullscreen)
	{
		// Reset the Display

		ChangeDisplaySettings(NULL, 0);

		// Change the window style

		m_dwStyle = WS_VISIBLE | WS_BORDER | WS_MINIMIZE | WS_CAPTION | WS_SYSMENU | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;

		// Set the new window style

		SetWindowLong(m_hWnd, GWL_STYLE, m_dwStyle);

		// Change the size of the window

		if (!SetWindowPos(m_hWnd, HWND_TOP, 0, 0, 800, 600, NULL))
			return(0);

		// Display the Cursor

		ShowCursor(TRUE);

		// Display the window

		ShowWindow(m_hWnd, SW_SHOWNORMAL);
		
		// Update the fullscreen flag

		m_bFullscreen = FALSE;
	}

	return(1);
}