I'm sorry to hear that you're having this issue.

Try switching it on by holding it in the on position for about 10 seconds. If that still doesn't work, use a small paper clip and poke the reset button on the back of the unit. This should effectively reset the unit in the event that there's a software issue.

If that still doesn't work, it may be a physical or hardware issue. So if resetting the unit doesn't allow you to turn it on, you may want to send it in to service, and you can set that up by calling 800-SAMSUNG.