2.Turn off the computer.
3.Remove any peripheral devices connected to the computer.
4.Restart the computer.
5.Press F2 when the Sony logo appears. The BIOS Setup window appears.
6.Press the Right Arrow key 
to select the Exit menu.
7.Press the Down Arrow key 
to select Get Default Values. The message Load default values for all SETUP items appears.
8.Press Enter. The Setup Confirmation window appears.
9.Select Yes, and press Enter.
10.Select Exit (Save Changes), and press Enter. The Setup Confirmation window appears again.
11.Select Yes, and press Enter. The computer restarts.
If your computer continues to display the message "Operating system not found," and Windows does not start, use your supplied System Recovery CD(s) to restore the software titles shipped with your computer. See Using the System Recovery CD(s) for more information.
The System Recovery CD restores your computer to its original state, so user data and programs will be lost.
Why doesn't my computer respond or turn off?
It is best to turn off your computer using the Turn Off Computer command on the Windows Start menu. Using other methods, including those listed below, may result in loss of unsaved data.
Click Start on the Windows® taskbar, select Turn Off Computer, and then click Turn Off.
If your computer does not turn off, press Ctrl+Alt+Delete simultaneously. The Windows Task Manager dialog box appears, and you can turn off the computer from the Shut Down menu.
If your computer still does not turn off, press and hold the power button to turn off the computer.
Unplug the computer from the AC adapter, and remove the battery from your computer.
If your computer stops responding while playing a CD or DVD, press Ctrl+Alt+Delete simultaneously. The Windows Task Manager dialog box appears, and you can turn off the computer from the Shut Down menu.
Pressing Ctrl+Alt+Delete simultaneously or turning off the computer with the power button may result in data loss in files that are currently open.
Why won't the power management respond?
Your computer's operating system may become unstable if a lower power state, such as Hibernate, is initiated and changed before the computer completely enters the lower power state.
To restore the computer to its normal operating stability
1.Close all open programs.
2.Restart the computer by pressing Ctrl+Alt+Delete simultaneously. The Windows Task Manager dialog box appears, and you can restart the computer from the Shut Down menu.
3.If this procedure does not work, press and hold the power button to turn off the computer.
Why is the sound of my computer's fan so loud?
Use the PowerPanel utility to change the Thermal Control Strategy setting to Quiet. This setting slows down the CPU speed. See PowerPanel Help for more information.
