Q.What is a computer virus? Name some computer viruses that were popular in recent years.

Think of a computer virus the way you'd think of a cold. You catch a cold from someone else, and once it's inside you, it starts making copies of itself, using your own body's machinery to do it. A computer virus works the same way. It's a piece of software that sneaks into your computer, often hidden inside something you invited in — an email attachment, a downloaded game, a USB stick — and once it runs, it starts replicating. It doesn't just sit there; it actively spreads, and it can mess with your files, slow your machine down, or send copies of itself to everyone in your contact list.

The precise meaning matters here. A virus is a specific type of malware (malicious software), and the defining feature is that it needs a host. It attaches itself to a legitimate program or file, and it only "activates" when you run that program. That's why it's called a virus — it can't exist on its own; it borrows the life of something else. This is different from a worm, which spreads across networks by itself without needing to attach to a file, and different from a Trojan horse, which disguises itself as something useful but doesn't replicate. For a commerce or humanities student, you don't need the technical code — you need the behaviour. A virus is a self-replicating hitchhiker.

Why should you care? Because in any modern workplace — a bank, a law firm, a government office, a media house — the data on a computer is often worth more than the machine itself. A virus can corrupt financial records, lock you out of your own documents, steal customer information, or turn your computer into a zombie that attacks other systems without your knowledge. The damage isn't just technical; it's financial and reputational. A single infected laptop in an office can bring down an entire network, and the cost of cleaning up can run into lakhs of rupees. So understanding viruses isn't about becoming a programmer — it's about knowing how to protect something valuable.

Here's how a virus typically gets in, and what it does once it's there:

• Entry points: Email attachments (especially from unknown senders), pirated software, infected USB drives, and links in messages or on websites. The common thread is that you, the user, are tricked into running something.
• What it does: It might delete files, corrupt data, slow your system, display unwanted ads, or quietly record your keystrokes to steal passwords. Some viruses are designed to stay hidden for months, gathering information.
• How it spreads: It often sends itself to everyone in your email contacts, or copies itself onto any USB drive you plug in. That's how a single infection becomes a network-wide problem.

The key idea to hold onto is trust. A virus exploits your trust — in an email from a friend, in a download from a familiar-looking site, in a USB stick someone handed you. That's why the first line of defence isn't technical; it's behavioural. Don't open attachments you weren't expecting. Don't plug in unknown devices. Don't download software from random websites. Antivirus software is a safety net, but it's not a substitute for caution — it can only catch what it already knows about, and new viruses appear every day.

For a commerce or humanities student, the practical takeaway is simple. You will likely work with sensitive information — client records, financial statements, legal documents, creative work. A virus isn't just a "tech problem" you hand to the IT department; it's a risk to your work and your reputation. Knowing the basics — what a virus is, how it spreads, and how to avoid it — is a professional skill, not a technical one. It's about protecting the trust others place in you with their data.