HP Notebook Restart Instead Of Shutdown?

My wife's daughter has an HP Pavilion dm4-2070 notebook with Windows 7 Professional.It had been working properly, but for the past week it will not shut down when you select Shut down from the Start menu; instead it restarts. It also won't hibernate properly; after about 10 seconds it resumes. It does seem to sleep properly, for example, when you close the cover. And it will shut down if you press and hold the power button for 10 seconds.I see a lot of posts on other forums with similar problems, but few solutions that seem to work. I have tried many of the suggestions (checking the shutdown and power settings, ensuring the network adapters can't wake up the computer, running SFC, updating the BIOS to the