To enter standby mode:
•Click Start→ Shut Down→ Stand by.
or
•Depending on how you set the power management options in the Power Options Properties window or the QuickSet Power Management Wizard, use one of the following methods:
¡Press the power button.
¡Close the display.
¡Press <Fn><Esc>.
To exit standby mode, press the power button or open the display depending on how you set the power management options. You cannot make the computer exit standby mode by pressing a key or touching the touch pad or track stick.
Hibernate Mode
Hibernate mode conserves power by copying system data to a reserved area on the hard drive and then completely turning off the computer. When the computer exits hibernate mode, it returns to the same operating state it was in before entering hibernate mode.
NOTICE: You cannot remove devices or undock your computer while your computer is in hibernate mode.
Your computer enters hibernate mode if the battery charge level becomes critically low.
To manually enter hibernate mode:
•Click Start→ Turn off computer, press and hold <Shift>, and then click Hibernate.
or
•Depending on how you set the power management options in the Power Options Properties window or the QuickSet Power Management Wizard, use one of the following methods to enter hibernate mode:
¡Press the power button.
¡Close the display.
¡Press <Fn><Esc>.
NOTE: Some PC Cards or ExpressCards may not operate correctly after the computer exits hibernate mode. Remove and reinsert the card (see Installing a PC Card), or simply restart (reboot) your computer.
To exit hibernate mode, press the power button. The computer may take a short time to exit hibernate mode. You cannot make the computer exit hibernate mode by pressing a key or touching the touch pad or track stick. For more information on hibernate mode, see the documentation that came with your operating system.
Configuring Power Management Settings
You can use the QuickSet Power Management Wizard or Windows Power Options Properties to configure the power management settings on your computer.
•To access the QuickSet Power Management Wizard, 
icon in the taskbar. For more information about QuickSet, click the Help button in the Power Management Wizard.
•To access the Power Options Properties window, click the Start button→ Control Panel→ Performance and Maintenance→ Power Options. For information on any field in the Power Options Properties window, click the question mark icon on the title bar and then click on the area where you need information.
Charging the Battery
NOTE: With Dell™ ExpressCharge™, when the computer is turned off, the AC adapter charges a completely discharged battery to 80 percent in about 1 hour and to 100 percent in approximately 2 hours. Charge time is longer with the computer turned on. You can leave the battery in the computer for as long as you like. The battery's internal circuitry prevents the battery from overcharging.
When you connect the computer to an electrical outlet or install a battery while the computer is connected to an electrical outlet, the computer checks the battery charge and temperature. If necessary, the AC adapter then charges the battery and maintains the battery charge.
If the battery is hot from being used in your computer or being in a hot environment, the battery may not charge when you connect the computer to an electrical outlet.
The battery is too hot to start charging if the 
light flashes alternately green and orange. Disconnect the computer from the electrical outlet and allow the computer and the battery to cool to room temperature. Then connect the computer to an electrical outlet to continue charging the battery.
For more information about resolving problems with a battery, see Power Problems.