Since that time, I have had several questions from readers asking if there was a way to reverse the process. First, go to the Start Screen and type "users" to get search results.
Seriously, you just click a couple buttons and everything should be set. Just make sure you don't put it off too long: if you don't update within a year from Wednesday, you'll have to pay for it.
But the bad news is that you may not be able to update this week, even though Windows 10 is coming out. If your version of Windows is as up to date as it can be, you should see that a Windows icon has appeared in your task bar.