Malware is a new term used to describe malicious "mal" software "ware" that has no other purpose other than to destroy or disrupt a computer. Spyware and adware are considered to be malware.
Adware is a software program that also is attached with free downloads of many kinds. What adware does is cause pop ups on your computer, even when you're done with the initial site you visited. That means that anytime you're on your computer, surfing, checking e mail, or even working, annoying pop ups will appear.
There are ways for your to protect your computer. The first is for you to perform an on demand scan of your computer on a regular basis with anti spyware software. It is suggested that you re-boot your computer after the initial scan and then re-scan to make sure that there are no "ticklers" left behind on your computer. These ticklers are designed to reinstall spyware. Don't forget to run your regular anti virus software on a regular basis.
Next, stay away from free downloads. Don't open up unsolicited e mail from anyone. Delete it from your server without opening it.
It seems wrong that people can do this to you, and it is. It would be nice if it was against the law too. Well, someday it might be. There is a case in court in the State of New York right now. The State is suing a Los Angeles based company called Intermix Media for placing unwanted spyware on computers. If the State of New York is successful it could be the end of spyware.