Lenovo IdeaPad Y510 7758 User Manual page 39

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 57.
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.
The computer does not return from sleep mode, or the sleep indicator stays
on and the computer does not work.
If the computer does not return from sleep mode, it may have entered sleep or
hibernation mode automatically because the battery is depleted. Check the sleep
indicator.
If the sleep indicator is on, your computer is in sleep mode. Connect the AC adapter
to the computer; then press any key or the power button.
If the sleep indicator is off, your computer is in sleep/hibernation mode or power-
off state. Connect the AC adapter to the computer; then press the power button to
resume operation.
If the system still does not return from sleep mode, your system has stopped
responding, and you cannot turn off the computer; reset the computer. Unsaved data
may be lost. To reset the computer, press and hold the power button for 4 seconds or
more. If the computer is still not reset, remove the AC adapter and the battery.
Chapter 3. Troubleshooting
34