Airline power ports only supply 72 watts of power. I just bought a new laptop (a P4) a few weeks ago and it requires 120 watts of power in order to function. Most people may not be aware of this limitation on the aircraft. If you read the back of your power adapter that came with your laptop and look at the output rating on it, it should say how many watts your laptop needs. If you have used it suceesfuly in the past, then this is obviously not the case, but others should be aware of this.