It is a computer software used to prevent, detect and remove malicious software.

These are an examples of

It is active in the operating system area,

One of the most prevalent viruses as they hit the office programs.

It spreads in the files when opened and increases the size.

It is trying to hide from anti-virus software, but easy constipation.

It is a fast-moving virus that uses file or boot infectors to attack the boot sector and files.

It is one that can transform based on the ability to translate, edit and rewrite its own code.

It is a program that copies itself to hardware, it comes through the network and it copies itself several times to the device until the machine slows down.