Go into Control Panel, then go into Power Options. Whatever "plan" you are running in Power Options, Balanced, Power Saver, click the "Change Plan Settings" of that plan and tell it when to turn off the display (if ever) and when to put the computer to sleep (if ever).
When in the "Change Settings for the Plan" screen, click on the "Change Advanced Power Settings" link, it should be in blue. A new window will open, called "Advanced Settings", and in this window the first item will be "Require a password on wakeup". Change the setting to "No". If it is not clickable you will first have to click on the link "Change settings that are currently unavailable", then you will be able to change the password setting.