After connecting the projector to the laptop, do the following:
1. Open your presentation in PowerPoint.
2. Select "Slide Show" | "Set Up Show" item.
3. Select "Secondary monitor" in "Display slide show on" box.
4. Check "Show Presenter View" box.
5. Click OK.
Now start slide show. You would be able to see the notes on the laptop and
slide show on the projector.
PowerShow - View multiple PowerPoint slide shows simultaneously