I briefly removed BitDefender AV 2008 today prior to installing BitDefender AV 2009. I guess a rogue program used this brief period to install itself on my Win XP SP3 computer. I have run a BitDefender Deep Scan, Lavasoft Adaware, and SpyBot S&D to no avail whatsoever. It appears the Advapi program is the culprit but I do not know what to do to remove it. Any help would be greatly appreciated.

Two errors are referenced in the Event Viewer - Security tab and they occur approximately every 30 minutes:

Event Type: Failure Audit
Event Source: Security
Event Category: Account Logon
Event ID: 680
Date: 8/18/2008
Time: 8:31:18 PM
User: NT AUTHORITY\SYSTEM
Computer: WARREN-7RZ2A5ED
Description:
Logon attempt by: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0
Logon account: Warren Strickland
Source Workstation: WARREN-7RZ2A5ED
Error Code: 0xC000006E


For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Event Type: Failure Audit
Event Source: Security
Event Category: Logon/Logoff
Event ID: 529
Date: 8/18/2008
Time: 8:31:18 PM
User: NT AUTHORITY\SYSTEM
Computer: WARREN-7RZ2A5ED
Description:
Logon Failure:
Reason: Unknown user name or bad password
User Name: Warren Strickland
Domain: WARREN-7RZ2A5ED
Logon Type: 2
Logon Process: Advapi
Authentication Package: Negotiate
Workstation Name: WARREN-7RZ2A5ED

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

After trying a variety of antispyware solutions, I decided to uninstall BitDefender 2009. Upon rebooting, the error messages in the Event Viewer - Security Tab referenced above disappeared. Thus, it seems that BitDefender itself is causing this problem. Has anyone experienced these error messages since installing BitDefender Antivirus 2009?

Sorry, I'm not going to be of any help to you but yes I'm experiencing the exact same thing. I assume it started with BD 2009 but my log file doesn't go back far enough to notice the exact date. 95% of the time it's exactly every 1/2 hour. I've been trying to find the problem with no success, sorry.