How to Conserve Your Laptop's Battery Using Power Options
You can use the Power Options feature to help your laptop's battery last longer. You can also avoid using certain devices or ration their use to save a modicum of power. For example, by setting a lower resolution and fewer colors on the display, you cause the computer to use fewer video resources, although those overall savings are minor.
The real control happens by setting timeouts in the Control Panel's Power Options window or dialog box. In Windows Vista, use the Power Options dialog box to choose a plan: Balanced, Power Saver, or High Performance. Note that Power Saver gives you the longest battery life. (You can fine-tune the options and settings by clicking the colored text labeled Change Plan Settings.)
In Windows XP, use the Power Schemes tab in the Power Options dialog box, as shown here. That's where you can disable or time-out certain laptop features and help extend battery life in a dramatic way.
Note the two major items in the figure: Turn Off Monitor and Turn Off Hard Disks. You can direct Windows to turn off those power-sucking hardware leeches after a given period of inactivity, greatly saving battery life.