My main firewall/anti-virus/anti-spyware program is Zone Alarm Internet Security Suite.
I also have Malwarebytes' Anti-Malware 1.36, which I run periodically.

It has been repeatedly finding a Trojan.Agent in a folder called A on our computer. It does not name a specific file in that folder that is infected. Here is the text of the most recent log file:

Malwarebytes' Anti-Malware 1.36
Database version: 2036
Windows 5.1.2600 Service Pack 3

4/24/2009 2:02:44 PM
mbam-log-2009-04-24 (14-02-44).txt

Scan type: Quick Scan
Objects scanned: 81846
Time elapsed: 2 minute(s), 17 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 0
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 1

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
(No malicious items detected)

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
C:\A (Trojan.Agent) -> Delete on reboot.

I have run SuperAntiSpyware and Zone Alarm Anti-Virus and Anti-Spyware, and none of those programs find this Trojan. Malwarebytes Anti-Virus does not find this Trojan when run in Safe Mode, only in regular mode. I have cleared all system restore points, I have disabled Zone Alarm so it will not run on reboot and I have run Malwarebytes' Anti-Malware and rebooted into regular mode when Malwarebytes' Anti-Malware finds this Trojan, but it is still there.
(I re-enabled Zone Alarm after trying the above steps).

It confuses me that Malwarebytes' Anti-Malware does not name a specific file in the folder as being infected with this Trojan. Is this normal? Is this a false positive? Any help anyone can give would be much appreciated.

Operating System:Windows XP Home Edition
Software Version:8.0
Product Name:ZoneAlarm Internet Security Suite