How To Use System Restore in Windows 10, 8, or 8.1

1. Open Control Panel. Check out that linked how-to if this is your first time, or just search for it from the Windows 10 Cortana/Search box or the Windows 8/8.1 Charms Bar.
2. Tap or click on System and Security within Control Panel.
3. In the System and Security window that's now open, click or tap System.
4. On the left, click or tap the System protection link.
5. From the System Properties window that appears, tap or click the System Restore... button. If you don't see it, make sure you're on the System Protection tab.
6. Tap or click Next > from the System Restore window titled Restore system files and settings. If you've previously performed a System Restore, you may see both an Undo System Restore option, as well as a Choose a different restore point option. If so, select Choose a different restore point, assuming you're not here to undo one.
7. Select the restore point you want to use from those in the list. If you'd like to see older restore points, check the Show more restore points checkbox. All restore points that are still in Windows will be listed here, so long as that checkbox is checked. Unfortunately, there is no way to "restore" older restore points. The oldest restore point listed is the furthest back you can possibly restore Windows to.
8. With your chosen restore point selected, tap or click the Next > button.
9. Confirm the restore point you want to use on the Confirm your restore point window and then tap or click the Finish button. If you're curious as to what programs, drivers, and other parts of Windows 10/8/8.1 this System Restore will impact on your computer, select the Scan for affected programs link on this page prior to starting the System Restore. The report is informational only, but might be helpful in your troubleshooting if this System Restore doesn't fix whatever problem you're trying to solve.
10. Tap or click Yes to the Once started, System Restore cannot be interrupted. Do you want to continue? question. If you're running System Restore from Safe Mode, please know that the changes it makes to your computer will not be reversible. Don't let this scare you away - chances are, if you're doing a System Restore from here, it's because Windows isn't starting properly, leaving you with few other options. Still, it's something you should be aware of. Your computer will restart as part of a System Restore, so be sure to close anything you might have running right now.
11. System Restore will now begin reverting Windows to the state it was in at the date and time logged with the restore point that you chose in Step 7. You'll see a small System Restore window that says Preparing to restore your system..., after which Windows will almost completely shut down.
12. Next, on a mostly empty screen, you'll see a Please wait while your Windows files and settings are being restored message. You'll also see various messages appear underneath, like System Restore is initializing..., System Restore is restoring the registry..., and System Restore is removing temporary files.... All in all, this will probably take around 15 minutes. What you're sitting through here is the actual System Restore process. Do not turn off or restart your computer during this time!
13. Wait while your computer restarts.
14. Sign in to Windows as you normally do. If you don't use the Desktop and aren't switched there automatically, go there next.
15. On the Desktop, you should see a small System Restore window that says "System Restore completed successfully. The system has been restored to [date time]. Your documents have not been affected.".
16. Tap or click the Close button.
17. Now that the System Restore is complete, check to see that whatever issue you were trying to fix is actually corrected.