Occasionally, some laptops may fail to properly power on or boot up correctly. Pressing the power button may result in no action, or sometimes the LEDs may just flash on momentarily and then back off without the system actually going through normal start up.
The cause may be some corruption of some bits of memory that affect how the power switch is read since the power switch on modern PCs doesn't actually switch power directly. The following procedure will remove the primary power sources of AC and main battery, and then drain residual capacitance by pressing the power switch several times. This will clear out stored values that may be corrupt, but will not affect data on the drive.
Power off your laptop.
Disconnect AC adapter (if it's connected).
Take off the battery.
Press and hold power button several time for several seconds each time.
Release power button.
Put in back the battery and reconnect AC.
If the system now starts up and produces the Lenovo or ThinkPad screen, press F1 or appropriate key to enter system BIOS. Select the option to reload BIOS defaults, then select the option to save and exit (ofter F9/F10)
This will rewrite BIOS values in memory. You can go back to BIOS and change settings that you previously customized, if needed.
Sometimes, reloading BIOS defaults can be useful after a BIOS version upgrade is performed, if there are abnormal symptoms noted. This does not roll back to previous version of BIOS, but does rewrite the feature settings.
The procedures above does not reset the operating system back to factory settings. If you wish to reset your PC's operating system back to factory, please reference Windows 8 features to reset to factory, or for XP, Vista, or Windows 7 clients, please make use of Lenovo's hidden system partition via Rescue & Recovery or One Key Recoveryapplications, depending on system model.
CAUTION: Resetting your OS will wipe out all your data! Be sure to back up all application and user data before resetting the OS to factory.