Virus attacks and intrusion attempts have been causing lots of troubles and serious damages to almost all the computer users. Ever the day, one starts using a computer, virus infection becomes an issue of concern. One is always left in a frightened situation, worried about the security of crucial data, completion of mission critical tasks and achievement of important goals. Antivirus software currently available is particularly suitable for detecting and eliminating known viruses. This traditional concept is becoming obsolete because it doesn’t do anything about new threats. Encrypted viruses pose a major headache. These are viruses coded using encryption software, which cannot be identified by antivirus software. The only product which can defend against these is antivirus software with so-called “sandboxing” abilities. This means that they can track down and neutralize viruses despite their encryption. This is modeled on the multiple operating systems at the same time concept. It allows us to run malicious code in a protected environment so that the code can’t harm our data. Sandboxing can protect our system against unknown threats because it operates within a few simple rules. We could, for example, define our system registry as being off-limits to changes. Sandboxing is where an antivirus program will take suspicious code and run it in a Virtual Machine (secure from the rest of the system) in order to see exactly how the code works and what its purpose is. The proactive antivirus technology basically involves enclosing a running application in what is called a “SANDBOX”. The sandbox is responsible for trapping downloaded applications in a controlled environment such as the temporary files folder where it monitors them for malicious code. This means that before we have a chance to release a potentially harmful virus into our network, the software will lock it away from critical network resources.