1, laptop operating system (in Windows XP, for example), enter the "power options". "Power schemes" option for "always on" and "turn off monitor" and "turn off hard disks" setting for the shortest possible time, and system standby is set to "never".
2, in the "power options", "alert", uncheck all alerts option, designed to let the battery completely drain until shutdown.
3, set finished, close all applications, turn off WIFI, unplug the power adapter, battery-powered. Do not do anything until the automatic shutdown after running out of batteries. After discharge is complete, connected to the power adapter, batteries, a battery calibration is finished.
If after correction for laptop battery battery battery life is not very clear, it may be due to the aging of the battery itself, if the notebook battery life to normal, not recommended battery calibration.