When you people say you've tried unplugging, are you referring to the power cord (which may be a USB cable) or the HDMI cable? Make sure you're unplugging the power. If you don't see the startup animation when you reconnect the power you haven't unplugged the correct cable.
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I was experiencing the same issue. The new features screen was displayed, and there was no way to exit out either using my remote or the Roku app on my handheld as a remote. Unplugging the power supply did the trick (I did not remove the HDMI, just unplugged the power). I waited a few minutes before plugging it back in.