First thing you should make sure whether we are defended by these worms, virus definitions, signatures and updates that your antivirus software is always downloading. Antivirus software provides the identifiable characteristic or finger prints for all malicious programs and this leads to specific scanning and the antivirus programs takes all the updates and stores it in the internal database. The antivirus software checks and matches the new files which are introduced in your PC via mails.
The computer users should realize that virus definitions can easily identify the know viruses. But just think of the new malicious software, malware, Trojans coming out daily to affect your PC.Nowadays N numbers of malicious programs are released by the spammers. So at this situation there is no possibility to detect the dangerous line of code which is going to affect our PC so we intend to go for generic scanning method. This type of scanning is used in larger networks and the scanning is done in the server. Antivirus providers use generic scanning to construct new virus and generic scanning method will be used by the single user in near future.
Heuristic just checks for the virus definition and find out the suspicious code. Sandboxing checks the antivirus program and detects the suspicious code and runs it in the virtual machine and checks the working flow of the suspicious code. Heuristic and sandboxing belongs to generic scanning method.
Well this is the quick review of how antivirus works. So please protect your PC with Antivirus software
Guard your PC and stay cool with internet security software.