In one sentence, describe what the following article is about:

If your internet connection was working a few days ago, but isn't anymore, you may be able to fix the problem by performing a system restore. This will roll back your computer's settings to the date that you select. Any changes made to the system since the date will be undone. This means that programs that you've installed since the selected date will be removed, and settings will be reverted. A system restore will not affect your personal files. The fastest way to open it is to search for it, though the process varies a little depending on the version of Windows you are using:  Windows 10 and 8.1 - Click the Start button and type "recovery". This will load the Recovery window in the Control Panel. Select "Open System Restore". Windows 7 and Vista - Click the Start button and type "restore". Select "System Restore" from the list of results. Restore points are created automatically whenever a change is made to your system files, such as installing a program or driver. Windows will choose the most recent restore point automatically. To view all available restore points, check the "Show more restore points" box. Choose a restore point from a date when you know your wireless adapter was working. Since restoring will roll your computer back to the date you select, programs that have been changed in that time will be affected. Click the "Scan for affected programs" button to see what will be removed or added back to your computer during the restore. Remember, your personal files will not be affected. Once you've selected your restore point and confirmed that you want to restore, Windows reboot and roll back. This may take a few moments to complete. Once the restore is finished, Windows will load and you will be informed that the restore was successful. If there was a driver or software problem causing a problem with your wireless adapter, restoring to a point before the problem occured should fix it. If you still can't get your wireless adapter to turn on, you may have to get your computer repaired or replaced.

Summary:
Know when to do this. Open the System Restore utility. Choose your restore point. Check to see what programs restoring will affect. Begin the restore process. Test your connection.