Hi there
Your current Power Settings are probably set to optimise the power management and conserve battery power. I use a laptop too, but always run it via mains power, so I have configured it not to hibernate, etc., if it is idle for a few minutes. Would suggest that you check your settings by clicking on Start > Control Panel > Power Options.
From the Power Options Properties box, you can select the power scheme that will best suit you, when running via the mains, or the PC's battery pack. Hope this helps