Change what the power button do - Windows 7

Click Start, go to Control Panel and click Power Options.  Click Choose what the power buttons do.

Change the Power and Sleep button settings and click Save changes.

Change Power Saving Settings - Windows 7

Click Start go to Control Panel and Click Power Options.
Note : If the control panel is in the category view click Hardware and Sound to access Power Options.

Select the Power Plan as Balanced and click Change Plan Settings

Change the Sleep and Display Settings

Advance users can click Advance power settings where you can configure the power options for each hardware separately.