Computers are a basic necessity in this new techno- age and are required by people for anything they can imagine. You can perform a number of activities ranging from storing data, sending mails, chatting, trading, shopping and many more with the help of your computer. Many times you have to submit your personal data or access some unsecured sites on the internet which can prove to be harmful if there is a virus on your computer.A virus can easily harm your computer system and your important files or some personal confidential data. To avoid this situation one can install antivirus firewall software on the computer. It is said that no antivirus software can protect your computer system completely because there are innumerable viruses affecting the systems every now and then. But, each of it has its own features and specialty. You can download the antivirus software online and install it in your computer or buy it from the market. There is a huge variety of these softwares available in the market. You can choose the one that fits you according to your needs and requirements.The real time protection softwares are very beneficial and give you an immediate response if you are trying to access any corrupted files or sites. They protect your computer against all kinds of viruses. Their response is usually in the form of messages that appear as pop ups. Before choosing any kind of antivirus you need to keep some things in mind. The program you are installing should be compatible with your computer system. The antivirus program has certain software and hardware requirements which should be fulfilled by the PC system. The software which you choose should be easy to install and have certain default configurations. It is better if the software you are installing has automatic update feature. Your antivirus firewall software should be able to protect your system from viruses like spam, phishing attacks, worms, Trojans, spyware, key loggers, password hackers, adware and rootkits. A good antivirus program scans your email inbox to check if there are any kind of viruses or dangerous web links included.Thus, these are the important features or conditions which should be considered before purchasing any kind of software. It is very important that a person installs the best antivirus security software in his system to protect it against viruses and harmful threats. Resource optimization is another feature which a person should consider before buying the software.