Concerning to:Kaspersky Anti-Virus for Windows Workstations version 6.0.4.x
Heuristic analyzer can detect malware in executable files, sectors and RAM. Characteristic features of the heuristic analyzer are flexible architecture and a combination of different methods. These features allow detection of the greatest number of malware infections with minimal false positives. This component analyzes the chain of malware intrusions in the system.
Heuristic analyzer uses the following components: File, Mail and Web Anti-Viruses.
Proactive defense is a wider notion. It is designed around monitoring and analyzing the behavior of all programs installed on your computer. Kaspersky Anti-Virus makes a decision based on the actions executed by an application: is the program dangerous? Proactive Defense protects your computer from both known viruses and from new ones that have yet to be discovered.