Hi there, I have a 18month old HP NX8220. the battery was replaced under warranty (just 6 months ago). two days ago, while the laptop was sitting on the bench, (shutdown and unplugged from power) the lights just started flashing. I tried to boot it up but it would'nt start (although was trying to). Eventually I just kept my finger on the power button for a few seconds and it powered up. Ran the usual checks, all seemed fine. Now, today its done the same again. What could be causing this?