Event Viewer – Security

Ok, so I have Win 2003 Standard server. I log in remote and I get “Security Log Full” I go into the security log and clear it. I then set it “overwrite events as needed” click ok and everything seems ok. I then log in later and it give me the same error. Also, my setting for my even viewer go back to “overwirte events older then blank”

any advise appericated.

Thanks