Computer viruses are very real and, in some cases (such as with ransomware viruses), can even corrupt data files.
A typical computer virus may:
- Slow your system down (although slow performance is usually caused by other types of problems).
- Mail copies of itself to everyone in your address book. Embarrassing and annoying, but not fatal to the computer system.
- Do nothing obvious except reproduce, and attach copies of itself to files and any files it can find on any connected media.
However, some viruses are actively destructive. They can shut your computer system down, erase files, alter or corrupt data files, and spread to any other connected computers, drives or media. They can affect the entire computer system by damaging Windows system files or damage just specific types of widely-used files such as: Word documents, Excel spreadsheets, and even Keystroke data files.
To prevent virus infections, install and continually update virus protection software on each workstation and/or server. Use firewalls on any computer systems or networks with an Internet connection.