One of the ways you can easily protect yourself against malware and viruses is by running as a "Standard" or "Limited" user in Windows. When you run as administrator, programs can easily get full access to your system, including those that might be installed without your knowledge. But when you run as a standard user, you may run into an issue where a program won't run because it requires more permissions. An example of software that would require additional permissions would be a screen recording program. When this happens, you can elect to run that individual program as administrator.
Sarah accidentally spilled wine in her computer, so she's ordered a new one. She's borrowing a computer from a friend in the interim. She has a variety of email accounts though, and she wants to access those, but she doesn't want to leave her account information saved on that computer. Sarah should create her own account on that PC. Then, before she gives back the computer, she can just delete that account. Sarah can just go into Users section of Control Panel and make a new account with administrative privileges. Then log out of her friend's account, and log into that account.