This problem can occur when Windows encounters an error. There is a setting in Windows for each user that instructs whether or not to display a username on the Welcome Screen.

To resolve this problem, please follow the steps below:

First, try pressing CTRL+ALT+DEL twice quickly to get a standard login box. This should allow you to login with your normal username. If this is successful, and you can login, try rebooting to see if this has fixed the issue. If the issue persists after the above, try this:

1. Go to Start > Run.
2. Type regedit [press Enter].
3. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\SpecialAccounts\UserList
4. Right click in the main part of the window, and choose to create a new REG_DWORD value, name it as LogMeInRemoteUser and set its value to 0.

When you save this and reboot, this username will no longer show in the Welcome Screen.