Won't Turn On, Won't Turn Off

[Yiab]

My Nexus 7 is stuck on the "X" screen.

After about 3 hours on the "X" screen, I rebooted it (held the power button for 10 seconds) and it went to black screen, then "Google" screen, then "X" screen, and it's stuck there again. It does this whether it's plugged in or not. I've read the advice here to let it cool down for about 20 minutes, but how can I do that when I can't turn it off either - do I just have to wait for the battery to drain? Also, it doesn't feel warm at all. In case it's relevant, this tablet has been working fine for almost a year, and it's not rooted.

Any help would be appreciated.

 

[mr_nobody]

I'm curious it rebooted when you held the power button for 10 seconds. I would have tried holding the power button for 30 seconds to power it off but if it reboots before then, I don't know what to tell you.