There is a picture on my screen and none of the controls work, How do I clear it?

[AC Question]

There is a picture showing on the screen. None of the touch screen controls will work. I cannot power off. I have removed and re-installed the card to no effect. The phone will receive calls, but I cannot answer them. I can access the pictures through a USB cable.

 

[Javier P]

Which phone do you have? Have you already tried holding the power button for 20 seconds? Depending on your device you'll need to hold this button for much longer.