A computer virus is software with malicious code that can self-replicate and spread from one file to another to produce a virus. It is designed in a way to alter the way a computer works. There must be a source to initiate the execution of the virus. Malicious code can get executed through the browser or remotely from another network computer. Therefore the user must be cautious of any signs of the virus in the system and take immediate precautions for protecting the device from the virus.

How does the computer viruses spread

A computer virus can spread from removable media such as infected USBs or CDs, downloads of infected freebies off the Internet, and email attachments with malicious software.

Types of Computer Viruses

There are different types of computer viruses encoded with malicious software that can cause damage to the system. Some of them are

• Boot sector virus: It can spread by attaching an infected removable media. 
• Browser Hijacker: The user can be directed to some unintended website by opening different websites, which can be due to the hijacked virus on the website.
• Web Scripting Virus: This virus spreads when a user opens a corrupted website and downloads the exploited web page codes on their device.
• Resident Virus: Any virus that resides in the computer memory itself is called the resident virus. It can activate when the operating system boots up.
• Polymorphic Virus: This virus changes its code every time a file infected with a virus is executed.
• File Infector Virus: This virus installed malware and damage-causing code in the file that could easily execute.
• Multipartite Virus: This virus infects both system sectors and program files and can spread in multiple ways.
• Macro Virus: It can infect the device when a user opens and downloads any email attachment with malicious software.

Detecting Virus in a Computer 

Some common signs of the virus in the system are-

• The sudden slow change in operations of computers or web browsers has been observed for some time, as frequent loading errors or crashing.
• Modified, missing, or deleted files and new installed programs or icons
• Connection to unknown websites and running or closing of Programs without consent
• Changes in your security settings and inability to download antivirus programs on the system.
• Unusual emails/social media messages being sent without your permission to a large audience
• The constant appearance of Pop-up advertisements. Change in a default search engine, such as New toolbars in the web browser

Ways to protect Device from Virus

Some measures of protecting devices from viruses are-

• Installing an Antivirus: The availability and range of different anti-virus programs vary. The level of security increases depending on pricing from low to high, respectively. Ensure more than one anti-virus can be installed, covering different security aspects.
• Regular Updating of Software: Regular updating of computers is essential as it ensures better functioning of the system. These updates also improve security measures preventing the system with the latest batch of viruses.
• Keeping a backup of System Data: Sometimes, formatting the system is essential to remove the corrupted files. Therefore a user must keep a backup of the data in their system to recover the lost files. Using a Strong password is a first-hand measure to protect the system from anyone trying to access the user’s account.
• Some websites, when loaded, can start the downloads on their own that consist of malware or suspicious content. One must cancel the downloads immediately if they didn’t authorise or should exit the webpage as it may contain more such malicious data.
• Install an Ad-blocker: Constant appearance of Pop-up advertisements can direct the user to suspicious websites that can steal the user’s data and install viruses. However, it is not always easy to identify whether the website contains malicious software; therefore, it is advisable to install an ad blocker that prevents the entry of such damage-causing advertisements into the system.
• A user must regularly run a virus scan at least once a week, and they should also avoid clicking on suspicious links.

Conclusion:

Even the most vigilant computer users download the corrupted files that damage their computers. Therefore a user must suspect the chance of a computer virus if their device crashes, slows down, or repeats error messages. The user must also download the anti-virus softwares as an important measure of protecting the device from viruses to limit the malicious softwares from entering the PC and must be installed in case of emergencies. Steps of identifying the types of computer viruses and eradicating them should get accessed on any signs of the virus in the system.