Can you please provide some more information such as which operating system you are using, since when are you facing the problem, what laptop model do you have and from which brand, etc.?
In case of Windows 7/Windows 8, it seems that your laptop's power plan settings are mis-configured. To resolve the problem you can:
> Go to Control Panel > System and Security > Power Options.
> From the right pane of the opened window, ensure that the Balanced (recommended) radio button is selected. If not, click to select the radio button to set the Balanced (recommended) power plan as default.
> Click the Change plan settings option representing the Balanced (recommended) power plan.
> From the next window, click the Restore default settings for this plan option.