Your questions.
What is ATs? Here is description.
http://www.atshield.com/Anti-Trojan Shield - High Performance Trojan Detectororganizer
Anti-Trojan Shield (ATS) is an advanced, highly effective blocker
of Trojans, worms, viruses, backdoors, malicious ActiveX controls,
and Java applets. It efficiently scans, detects, and removes malicious files,
while maintaining an exceptional level of personal privacy and security.
Without this tool, you definitely should worry about new Trojan horses and viruses,
but with Anti-Trojan Shield you have no need for concern. Its integrated update
utility always keeps the software on the cutting edge, fully armed for battle.
Found in
C:\Program Files\Quicktime ALternative
Details as shown in ATS
CaznovaIRCSpy v2.5 Server...-upx.exe
System XP
AV
Avast Home 4.6
Firewall
Zone Alarm Freeversion ( kept with latest version)
Sorry if info is irrelevant or inadequate; that is the best I can do