So you login to your computer every single day, but there's more than one account to choose from… either because you got the computer from somebody else, or some software package added a user account that you really don't want to see. So how do we hide that other account from the login screen?
There's a simple registry hack that you can do to hide accounts from the login screen, or you could alternatively delete the user account if you really don't need it. Both methods are listed below.
Manual Registry Hack
Open up regedit.exe through the start menu Run box, and then navigate down to the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\
CurrentVersion\Winlogon\SpecialAccounts\UserList
On the right-hand side you'll see a list of keys that correspond to user accounts that are considered "Special" and are not to be shown on the login screen.
Create a new DWORD value with the same name as the user name that you want to hide. You'll note that the actual username in the illustration was "OtherPerson" and not the description that was shown on the login screen.
To unhide the account, simply delete the registry key that you created.
The next time you log off you'll see that the other account is gone.
Hide User Account with Tweak UI
You can also use the Microsoft Tweak UI PowerToy to do the same thing. (Thanks to Gustav for reminding me to include this)
Just click on the Logon key in the left hand side, and then uncheck the box for "Show <username> on Welcome screen"
Login to Hidden Account
You can still login to the account even though it's not shown… You'll just have to use a little trick.
At the login screen, just hit the Ctrl+Alt+Delete combination twice in a row, and you'll be presented with the old-school login screen, where you have to manually enter the username.
Type the name and password of the other user, and login.
Delete User Account
Alternatively you can always delete the user account if you are absolutely sure that you don't need that user account anymore. Right-click on "My Computer" and choose "Manage"
Navigate down through "Local Users and Groups" and then Users, and then locate the username in the list that you'd like to get rid of.
Just right-click and choose Delete. Note that this step cannot be reversed, so make sure you only delete accounts you really really don't want anymore. If you are unsure, you can just hide them using the first option above.