Well, I'm not trying to make everyone's problems with their HP laptops look like the one I had, but there *has* been a design "flaw" with the robustness of the motherboard on certain models that HP has recognized publicly. Because of this HP has extended the warranty an additional year and my machine was repaired at no cost and in a short time. Last December I received an email from HP that told me to go to
http://h10025.www1.hp.com/ewfrf/wc/g...en&lc=en&cc=us for information on this extended warranty. I would suggest you go there first. It describes the symptoms of the problem so you can determine if your machine is one of those covered. My machine was "freezing" for a week before it incurred the same symptom as yours: not booting up. But several months back I had had the issue of my wireless card dropping out of the operating system configuration. So I had a good guess it was the same problem they were addressing with their extended warranty.
Tim O