When you start a Microsoft Windows XP-based computer in Safe mode, if you have the Welcome Screen enabled, not all user accounts are displayed on the Welcome Screen.
User accounts that do not have administrative privileges are not listed on the Welcome Screen. Users with Standard or Limited account types do not have access to start in Safe mode.
Log on with an account that has administrative rights, perform the necessary maintenance. After that, start the computer normally, not in Safe mode, and you can log on with any user account.