Lenovo IdeaPad U110 User Manual page 72

Chapter 4. Troubleshooting
Sleep or Hibernation Problems
The computer enters sleep mode unexpectedly.
If the processor overheats, the computer automatically enters sleep mode
to allow the computer to cool and to protect the processor and other
internal components. Check the settings for sleep mode.
The computer enters sleep mode (the sleep indicator turns on)
immediately after Power-on self-test (POST).
Make sure that:
The battery is charged.
The operating temperature is within the acceptable range. See
"Specifications" on page 96.
If the battery is charged and the temperature is within range, have the
computer serviced.
The critical low-battery error message appears, and the computer
immediately turns off.
The battery power is getting low. Connect the AC adapter to the
computer, or replace the battery with a fully charged one.
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