UAC stands for User Account Control.User Account Control (UAC) can help prevent unauthorized changes to your computer.Any time a program wants to make a major change to your computer, UAC lets you know and asks for permission.According to Microsoft “User Account Control (UAC) is a feature in Windows that can help you stay in control of your computer by informing you when a program makes a change that requires administrator-level permission. UAC works by adjusting the permission level of your user account. If you’re doing tasks that can be done as a standard user, such as reading e‑mail, listening to music, or creating documents, you have the permissions of a standard user—even if you’re logged on as an administrator.”
Lets see how you can launch it from Run menu in Windows 8.1.
1] Press Win + R keys together to launch Run menu.
2] In the run box type or copy and paste UserAccountControlSettings.exe and press the enter key.