Viruses are the bane of many a PC user’s existence. They can attack you through malicious web sites, corrupt important system files and even erase important data. However, you can keep yourself safe with anti-virus software. Anti-virus software comes in several types of packages — best of all, some of the most effective anti-virus tools are freeware. Virus detection can also be achieved through online checks. It is imperative to understand their necessity, especially since they can slow down system performance and prompt the user with unfamiliar commands. Normally, anti-virus software has three modes of detection:
1. Signature based detection — The most common method. It matches the contents of any infected files against a data base of virus signatures that are updated on a regular basis. This mode even examines files in pieces to detect the infected areas. However, constant updating of virus database definitions is essential.
2. Malicious activity detection – Monitors your system for suspicious behaviour. In case any suspicious activity is detected, the system initiates signature based detection. This is useful for catching unknown viruses that may not be listed in the database.
3. Heuristic based detection – The most system taxing mode of detection but the most effective for detecting unknown viruses. This is done through two methods: File analysis and file emulation. In file analysis, virus-like instructions that may be embedded in different programs rather than suspicious behaviour is investigated. If a program has instructions to format the C drive, for example, the anti-virus examines this program more closely. File emulation involves executing a program in a virtual environment and logging the actions that occur, according to which the anti-virus takes appropriate disinfection measures. As stated however, both methods of this detection requires large amount of system resources.
One of the most reliable anti-virus solutions available is AVG Free. It’s divided into three sections: Overview, Computer Scanner and Update Now. Overview provides info on the version running, last scan performed and the last definitions update. It also showcases all the option available like Link Scanner, E-mail Scanner, etc. and easily indicates whether they are up-to date (green) or outdated (red) along with their active status. If outdated, clicking on an option provides solutions. Computer Scanner allows you to edit scan settings for the entire computer or specific folders and files. Scan settings let you determine scan access priority (fast, automatic or slow), the use of heuristics, automatically healing/removing infections and more. Scans can be also scheduled to run at specific times, on start-up or even after every few hours.
The Update Now section is the most straightforward tab. It automatically connects online to fetch the latest virus database definitions for detecting matching virus signatures.
For more options, click on Tools > Advanced settings. You can schedule scans for different components on the basis of frequency, time of day and what not. You can also determine update priorities, proxy settings, types of file extensions to be detected by the Resident Shield, etc.
On short notice at any time, free anti-virus scans are also available online through several reliable sites such as:
Some essential tips to preventing virus infections: Always scan external media. Schedule daily scans and updates (at the minimum). Never ever execute files from unknown email senders or follow unfamiliar links.