Malware is programming or files that are developed for the purpose of doing harm. Thus, malware includes computer viruses, worms, Trojan horses, spyware, hijackers, and certain type of adware.
1. Virus - A program that when run, has the ability to self-replicate by infecting other programs and files on your computer. These programs can have many effects ranging from wiping your hard drive, displaying a joke in a small box, or doing nothing at all except to replicate itself. These types of infections tend to be localized to your computer and not have the ability to spread to another computer on their own. The word virus has incorrectly become a general term that encompasses trojans, worms, and viruses.
2. Spyware - A program that monitors your activity or information on your computer and sends that information to a remote computer without your knowledge.
3. Adware - A program that generates popups on your computer or displays advertisements. It is important to note that not all adware programs are necessarily considered malware. There are many legitimate programs that are given for free that display ads in their programs in order to generate revenue. As long as this information is provided up front then they are generally not considered malware.
a. Use a good free antivirus like Avast or Avira AntiVir.
b. Use an antispyware, spybot s&d and superantispyware.
c. Use antimalware, malwarebytes.