You can protect your computer from computer viruses using a few simple e-mail and web browser functions and some anti-virus software.

The internet can be a fun and exciting place to explore, but computer viruses travel around using it, and they could seriously damage your computer.

If a virus gets on your computer it can delete or even destroy files and software, and even deliver itself to your friends or work colleagues.

Replicators

Just like a medical virus, a computer virus can come in all shapes and sizes. And a computer virus can cause all kinds of different symptoms on your PC.

In general terms, a virus is a tiny little computer program that has the built-in ability to copy itself from one location to another.

Viruses spread from computer to computer

It does this by attaching itself to e-mail messages or hiding in the code of some programs.

As well as making copies of themselves to send to your friends, many viruses will delete files on your computer, or even interfere with your software.

That is why they aren't very popular amongst computer users.

Diagnosing a virus

That doesn't mean that everything that goes wrong with your computer is always a virus, but it does mean that a virus is something to avoid catching.

To spot whether you've got a virus on your computer, you should look for one or more of the following things:

• your computer being unusually slow
• new or regularly used floppy disks becoming unusable
• unusual error messages popping up on screen
• programmes crashing or slowing down when they're open
• documents or folders changing size, name or date
• unusually slow download speeds
• strange screen activity