I had a problem of hacking my program files whenever my dial up connection gets turned on. It was looking like remote access to my computer. That means someone was tracking my system movements, by which I got in trouble. But, soon I found solution over this. My uncle, who is a security engineer in IBM, had suggested me to install Kaspersky internet security. I followed their advice and get result within just 2 days. My system is now working flawlessly. As uncle suggested, there are some constraints before you purchase any security software as follow that you should check: Computer security is a field of computer science concerned with the control of risks related to computer use. The means traditionally taken to realize this objective is to attempt to create a trusted and secure computing platform, designed so that agents can only perform actions. The actions in question can be reduced to operations of access, modification and deletion. Computer security can be seen as a sub field of security engineering, which looks at broader security issues in addition to computer security. Computer security is a branch of technology known as information security as applied to computers. The objective of computer security varies and can include protection of information from theft or corruption, or the preservation of availability, as defined in the security policy. Computer security imposes requirements on computers that are different from most system requirements because they often take the form of constraints on what computers are not supposed to do. This makes computer security particularly challenging because it is hard enough. Furthermore, negative requirements are deceptively complicated to satisfy and require exhaustive testing to verify, which is impractical for most computer programs. Computer security provides a technical strategy to convert negative requirements to positive enforceable rules. For this reason, computer security is often more technical and mathematical than some computer science fields. Typical approaches to improving computer security (in approximate order of strength) can include the following: 1) Physically limit access to computers to only those who will not compromise security. 2) Hardware mechanisms that impose rules on computer programs, thus avoiding depending on computer programs for computer security. 3) Operating system mechanisms that impose rules on programs to avoid trusting computer programs. 4) Programming strategies to make computer programs dependable and resist subversion. Computer security is critical in almost any technology driven industry which operates on computer systems. The issues of computer based systems and addressing their countless vulnerabilities are an integral part of maintaining an operational industry. The aviation industry is especially important when analyzing computer security because the involved risks include expensive equipment and cargo, transportation infrastructure, and human life. Security can be compromised by hardware and software malpractice, human error, and faulty operating environments. Threats that exploit computer vulnerabilities can stem from sabotage, espionage, industrial competition, terrorist attack, mechanical malfunction, and human error. There are several approaches to security in computing; sometimes a combination of approaches is valid: 1) Trust all the software to abide by a security policy but the software is not trustworthy (this is computer insecurity). 2) Trust all the software to abide by a security policy and the software is validated as trustworthy (by tedious branch and path analysis for example). 3) Trust software to enforce a security policy with trustworthy mechanisms. (This is a computer security policy).