Tearing down your computer one code at a time
A virus is a thing that continues to multiply and takes up space/ destroys your computer. A virus needs contact to spread, this can be an email link etc. To avoid viruses use firewalls and security programs.
Seems like a thing you like, like a game or program but when opened and used it allows another person to access your computer and destroy/use it. To avoid these use trusted sites, and firewalls.
Spyware is a program that logs your keystrokes/sites visited and the info is sent to a person to use how they want. They can be added to Usb's and put in computers. To avoid this don't go to personal sites like banks on public computers, and use firewalls/protection programs.