Understanding Vista's New Network Connection Icons
Windows Vista's network connected icons that live in the system tray have a new feature: They let you know if you are connected to the internet, or just your local network. These new icons are especially useful when you are connected to a wireless network.
Connected to Internet
Notice the tiny globe, indicating connection to the internet. Mousing over the icon will also show the popup window, which will tell you exactly what you have access to.
Connected to Local network only
Notice that the globe icon is gone, indicating that you can't connect to the internet, but you can connect to local computers.
Not Connected
Maybe you should plug that cable back in ?
Windows Vista is definitely more polished than XP.