domain: windows sbs 2003 service pk 2workstations are xp prof. latest patches.roaming profiles.2 people need an answerI do too

User account appears to be corrupt. Windows sbs 2003 service pk 2; User has intermittant connections and sometimes she gets messages about access denied because of security threat.Have scanned for viruses and this is not the case. Any workstation that the user logs into acts the same way. She has a roaming profile. Can this user be fixed or re-authenticated? Event id: 1054 and 1521 userenv - user has windows xp latest patches.Have been trouble shooting for days. Is there a way to fix a corrupt user account in windows 2003 environment?Any suggestions would be greatful.