Open Computer Management
In the console tree, click Users.
Computer Management > System Tools > Local Users and Groups > Users
Right-click the user account you want to delete, and then click Delete.
To open Computer Management, click Start, and then click Control Panel. Click Performance and Maintenance, click Administrative Tools, and then double-click Computer Management.
When you need to remove user accounts, it is a good idea to disable the accounts first. When you are certain that disabling the account has not caused a problem, you can safely delete it.
A deleted user account cannot be recovered.
The built-in Administrator and Guest accounts cannot be deleted.
Local Users and Groups overview
Change the password for a user
Create a new user account
Delete a user account
Disable or activate a user account
Modify a user account
Rename a user account