If your uni-processor mobile Windows XP computer supports ACPI (Advanced Configuration and Power Interface) processor idle sleep state (C-states), and the computer changes the number of idle sleep states during transition from AC to DC power, and you disconnect the power cord while a program is running, you will experience decreased battery life when the operating system reevaluates the _CST processor object.
If the decreased battery life is only the result of the use of low power idle states, the following workaround should help:
1. Open a CMD.EXE window.
2. Type the following commands, pressing Enter after each line:
REG ADD "HKLM\System\CurrentControlset\Control\Session Manager\Power" /V IdleFrom0Delay /T REG_DWORD /F /D 10000000 REG ADD "HKLM\System\CurrentControlset\Control\Session Manager\Power" /V IdleFrom0IdlePercent /T REG_DWORD /F /D 50