Be Safe on the Internet
Malware is any malicious software.
Lets focus on the Viruses first. Viruses copy themselves. Therefore you might send a virus to someone else by accident and might think that its gone from your computer completely yet the virus only copies itself, staying in your computer and going to the others computer as well.
Next would be Spyware. Spyware takes your personal information without your consent. You would have just given all your information to an identity thief without you even knowing it.
Even though these things seem that are very hard to get out of your computer there is a way to avoid both of these situations. Downloading an AntiVirus Software is the easiest way to avoid getting a virus. The Software will make sure that whatever you're downloading won't do any harm towards your computer.