If it will -not- boot up and your computer is still on warranty... go back to the vendor and use your warranty.
Seeing as how opening up a computer voids the warranty in most if not all cases.
I have a laptop running Windows XP. It went into hibernation today and I can't get it out.
I have pressed the power button, which usually works, but not this time.
I have removed the battery for several minutes, but that didn't help.
Essentially, the laptop is dead. I can't get it to turn back on.