Draining residual power

[OFFtheWALL15]

To fix a problem, I was told to remove battery, press power button for 30 seconds and then put battery back in. They said its to drain residual power. When they say the draining power part I am confused. Will I need to plug in my charger once i get laptop turned on?

 

[Pinhedd]

To fix a problem, I was told to remove battery, press power button for 30 seconds and then put battery back in. They said its to drain residual power. When they say the draining power part I am confused. Will I need to plug in my charger once i get laptop turned on?

No. PC motherboards include a small 3.0 volt battery which powers several things independently from the PSU. These include:

• 
  The real time clock which enables the PC to track time even when it is powered off and disconnected from the PSU
  
  The firmware settings, if they are stored in volatile RAM. Newer motherboards store all firmware settings in non-volatile RAM (usually Flash memory).
  
  Some motherboards may provide power to the power control circuitry, but this is usually tapped from the PSU's 5.0 volt standby rail.

The motherboard includes a small buffer to ensure that power to the components that utilize onboard power remains uninterrupted. Depending on the motherboard's electrical design, the capacitors that construct this buffer may take several seconds to drain after the battery has been removed or disconnected.