Sony PCG-Z1M User Manual page 56

Using your notebook
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If you press the power button for more than four seconds, the computer will switch off automatically.
When the computer is in Hibernate mode, you cannot insert a disc.
Hibernate mode requires more time than Standby mode to be activated.
It takes more time to return to normal mode from Hibernate mode than from Standby mode.
Hibernate mode uses less power than Standby mode.
Do not move the notebook until its power indicator turns off.