I also have this problem. My tab got drained so when I got home, I plugged in the charger to the tab. Then I pressed the power button. So the tab opened but it hangs when the SAMSUNG logo is on the screen. I tried to wait it out for around 10mins but nothing happened, it remained in the SAMSUNG logo. So I tried holding the power button for 15secs to reboot but when it rebooted, the tab still hangs in the SAMSUNG logo.
Please help. I just bought this tab 3days ago. It is not rooted and so far I have installed only around 10 apps and games all from the market. Im not sure what caused this problem.