Those of us with laptops are constantly looking for the power outlet. Trying to keep the beast going without losing the letter you just wrote.
One thing you can do is check on the power modes available to you . Windows XP offers several power saving settings when on battery. Vista offers even more. Some laptop makers also offer a special interface with the laptop that can make it easier to adjust all the settings. Vista has by far the most adjustable settings.
If I left click on the battery icon I am presented with a choice of three modes.
Balanced, power saver and performance. They do just what their name suggests. Balance the power usage and performance, provide better battery life, provide better performance.
If you go on to power options you can then edit first the basic settings and, via a shortcut on that page, the advanced settings, over a dozen settings to help you squeeze out every last electron from that battery. If you get it twisted up and can’t seem to get it back right again there is a reset to default button on the same page.