Over the years, computer programs have evolved from being productive to being malicious. Malicious software programs are rampant these days; some of these are computer viruses, spam, spyware, and adware. Spyware and adware are both classified under malware, which means they are malicious software that changes system and registry settings of the operating system which in turn causes the computer to be unstable.

Adware in its basic form is a program that shows advertisements on your computer monitor. Once a computer gets affected by adware, windows showing advertisements may popup on the display even if the computer is disconnected from the Internet. Aside from displaying popup windows, adware can also add website shortcut links to a webpage browser's favorites folder and change the setting of your browser's homepage. Adware also redirects search engine search results to other websites, most often to websites that earn income out of the number of clicks or hits they gather.

Adware is usually installed on a computer system through false pretenses. Adware websites trick users into clicking links that will install the adware program onto their systems. Similarly, adware can also be installed through freeware and bundled software, among these are free FTP or file sharing programs. Users are normally eager to use free software, which made combining adware with freeware software a likely ""package.""

Adware takes advantage of the gullibility of users when it comes to using free things from the Internet. The most basic protection against adware would be for users to make sure the software they are planning to install comes from a credible source and does not include adware. Synonymously, users are advised to visit only trusted websites. When faced with a dialog box or a popup window during software installation or upon visiting a website, users are advised to read carefully before clicking on the ""OK"" or ""Yes"" option.

Aside from practicing safe web surfing, users may protect their computer systems by making sure the operating system is patched up or updated. Another solution would be to download and install ""Pop-up Blockers"" to stop popup advertisements from showing on the display. Antivirus software also provides protection against adware.