''ALTEC LANSING'' I believe are speaker manufactures. If I had to guess that light indicates the status of your onboard sound. The light is probably off if the onboard sound is muted or turned off. Look for a symbol next to the light to try and tell what its for. I just recently got called to help a friend with a new laptop. Her wireless wasn't working. It turns out she inadvertently turned it off by hitting a key on her keyboard. Laptops don't have a full size keyboard and some keys may have up to 3 or more functions depending on what other hot key you press. Anyway, laptops will have keyboard keys to disable your wireless adapter, onboard sound, etc, so you can save battery power. The various lights tell you if said device is on or off. Sometimes they just change color. The symbols next to the light are meant to tell you what its for but some of them are not obvious. You'll just have to go thought the owners manual.