Acer MF-550 User Manual page 57

2. Press down the Menu button again, and then push the Menu button to
the right four times to select POWER OFF. Once the massage of
POWER OFF appears on the screen, press down the Menu button again.
3. Now push the Menu button to the right or to the left to select a desired
time to turn off this MP3/Storage Drive. If select DISABLE, and the
power of this MP3/Storage Drive will always stay on.
4. When a selection is decided, press down the Menu button once to
confirm the selection.
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