I have an Acer notebook that sits alongside my desktop. Today, like every day, I hit the power button--and nothing happened. Well, not quite nothing: the power light came on and I heard the usual fan noise, but the screen stayed dark. And there was no hard-drive activity. In short, the notebook was dead.
I held down the power button to force a shutdown. Then I waited about 10 seconds and hit the button again. Same result: The notebook burbled but didn't boot.
I'm not one to take "won't boot" for answer, so I disconnected the power, removed the battery, flipped the notebook over, and unscrewed the plastic panels covering the hard drive and memory sockets. Notebooks get bumped around a lot, and if some plug-in component gets knocked even a little bit loose, the result can be, well, a dead notebook.
Everything looked okay, but I removed and reseated the memory modules anyway. Then I reconnected the power and presto: The Acer booted normally.
Obviously this won't work in all cases, but it's something to remember if your notebook ever wakes up dead.