One of the most frustrating thins is to come back to your computer and find that your download was interrupted when Windows when into sleep or hibernate mode. Here's how to temporarily prevent that from happening. Unless you plan on staying at your computer during the whole time it takes to download your file, this tutorial will show you how to temporarily disable sleep mode / hibernation. Once the download has completed, you can go back to your previous hibernate / sleep settings. This scenario can also be used to keep an email program running, for example - if you temporarily need client-side rules (mail filters) to run for a while . This tutorial applies to Windows 10, Windows 8 / 8.1 Pro, and Windows 7. (In fact, that's the trick we used when downloading the Windows 10 Preview ISO file.)
Note: what's the difference between "sleep mode" and "hibernation"? When Windows is asleep, it can quickly wake up - either when you open the laptop's lid, or when you mouse your mouse or hit a key on the keyboard in the case of a desktop. Hibernation is mostly useful for laptops and tablets: Windows takes a snapshot of the PC's current state and RAM, and stores it onto your hard drive. This lets the machine run much longer on battery, but takes longer to wake up than sleep mode. The "hybrid sleep" option protects desktops -to an extent- from losing data follow a power failure, while your PC was asleep.
Open the start menu, and type "
power" in the search field; then, click "Power Options", the first result listed under Control Panel. Whatever power plan is currently selected doesn't matter: just click on the "Change plan settings" on the right of your current plan's name. What you see next depends on whether you are using a laptop or a desktop PC:
For a desktop, pick "Never" in the "Put the computer to sleep" dropdown menu. On a laptop, pick that same value under that menu on the right (below "Plugged in") - we assume that you're not going to try downloading 4 gigabytes while running on battery :)
When you are done, click on the "Save changes" button. To remember to reset your power options to their original state, click on the "Change plan settings" link again, and leave the Control Panel window open. And change them back once your download has completed.
From this point on, your computer will stay turned on no matter what: the display will itself soon enough, and ultimately turn off, but the computer itself won't go to sleep. (Unless its running on battery and runs out of juice, or in case of a power failure, etc. - but all of these scenarios don't have anything to do with the operating system itself.)
Tip: if you're trying to conserve power at the same time, just set the monitor to turn off after just 1 minute, and adjust the current brightness to its minimum setting. In the case of a laptop, search for "lid" in the Control Panel, and change (temporarily) the "Change what closing the lid does" setting to "nothing" - you can then safely close your laptop, and it won't go to sleep or shut down Windows!