Virus: A type of malware that is often acquired through email attachments or thumb drives. It is known for being able to copy itself very easily, and it needs contact to spread. If an attachment containing a virus copies itself onto your computer, it can then send itself to every other person in your address book.
Spyware: Secretly obtains personal information. Mostly through key-logging, which is a tiny thumb drive inserted into a computer, and can record and collect everything anybody types on that computer. Found in libraries and other places with public computers.