To get rid of this alert is really easy:
1. Right click the start bar and click properties.
2. Go to the start menu tab and click customise.
3. Click on the advanced tab
4. Deselect "Highlight newlie installed programs"

Windows XP has moved everything around and there are so many new features that this was a tough one to find. By the way, this is only applicable if you have the new XP start menu not if you are using classic