When you use an account that is not a member of the Administrators group to try to log on to a computer that is running Microsoft Windows Server 2003 or Microsoft Windows XP, you may receive the following message in the "Log On to Windows" window:
The security log on this system is full. Only administrators can log on to fix the problem.
You can log on to the computer by using an account that is a member of the Administrators group, such as the built-in Administrator account. However, if you log on to the computer remotely, you may receive the following message:
The security log on this system is full
This issue occurs because no more events can be logged to the Security log on the computer. When events cannot be written to the Security log, only accounts that are members of the Administrators group can log on to the computer.