WARNING: I am NOT responsible for any expulsions or such if you do this at school/work! First, restart your computer.
Once you get to this screen, hold the power button on the computer until it turns off (no damage will be done, trust me).
Go to Windows/System32. Now do EXACTLY as I say, or you MIGHT break the computer. Under "Files of type," select "All files." Scroll down and find "cmd," then make a copy of it in the same folder (Ctrl-C, Ctrl-V). You should get a file named "cmd - Copy" or something like that.
Next, we need to find out what user is the local administrator for this PC. To do this, type "net localgroup Administrators" and look for any administrator that does NOT have your school/work domain in front of it, followed by a "/." As you can see, one of the admins is named "qwaszx." You will probably see a name like this, since schools/workspaces tend to make it a random string of letters and/or numbers to ward off people from entering it.
Now, we need to change that account's password. Type "net user <ACCOUNT NAME HERE> *" and type the new password twice. It will not show what you're typing, but your keystrokes are being registered. You can now log in to your admin account! However, schools/workspaces also like to disable the admin account you just changed the password for, so you might not be able to log in. There is a simple fix. If you get that message, go to the extra step below.