How to Find a Domain Usernameby Stephen Lilley ; Updated September 28, 2017
A domain is a group of computers that are all connected to each other over a type of network. The main difference between a domain and a regular network is that data transfers over a domain are regulated by a server, whereas a regular network does not have this feature. A computer's "user name" on a domain is called the "computer name," which you can check very quickly using the System Information tool built into Windows. In this context, "user" is the term used to describe one computer on the domain.
Click "Control Panel."
Click the Control Panel category link that reads "System and Maintenance."
Click the icon that reads "System." This will open your computer's "System Properties" window on the screen. The computer name of your specific machine, which is the user name that your computer employs to properly identify itself on the domain, is listed under the "Computer Name" category heading. You can also see the name of the domain you are connected to as well as any related settings.