Sony PCG-GRX500 VAIO User Manual page 140

The power management setting is not responding.
Your notebook's operating system may become unstable if it is interrupted or if you attempt to make changes before the
notebook completely enters a lower power state, such as Hibernate.
 To restore the notebook to its normal operating stability:
1. Close all open applications.
2. Restart the notebook by pressing the Ctrl+Alt+Delete keys simultaneously and then selecting
Restart from the drop-down list.
Note:
If this procedure does not work, press and hold the power button for four seconds or longer to shut down the notebook.
Page 140