My Ipod Touch was stucked

As the title mentioned, when I tried to turn off my Ipod Touch 4, it shown black screen with a running circle in the center.
The running circle keep going, and wait about 2 hours, still there.
Later I connect it to my PC, iTunes loaded automatically, but pop up with an error. Unknown device error code 0x8000065.
OK. First I want to do is to turn off the device and restart it.
I hold power button for a while, not working.


Finally, I Googled a tip to press power and Home button at the same time about 7 seconds.
Great tips, it works.
Ipod Touch was turned off and which apple logo shown when it restarted.
I don’t know why it happens, maybe one of the apps has problems.