Hi
Welcome to the HP Forums!
It is a terrific place to find answers and tips!
For you to have the best experience in the HP forum I would like to direct your attention to the HP Forums Guide.
How Do I Find My Model Number or Product Number?
I understand that you were using your laptop and closed the lid with the it still on. You returned an hour later and are unable to start the laptop now. You have tried turning it off and on multiple time and removed the battery and powered it on and off to no avail.
Here is a link to HP Notebook PCs - Computer Does not Start (Windows 7, Vista, XP) that should help.
Should you require further assistance please reply back with further details of the situation. Example do you see any lights flashing or hear any beeps?
Thank you for participating in the HP Forums! We want to help you as well as others who may experience a similar issue as you. Please consider marking the post that resolves your issue as "Accept as Solution" to help other community members!
To show appreciation for my efforts kindly click the Thumbs Up below.
Best of Luck!