Adware is software that displays advertisements on your computer without your permission, even if you're not browsing the Internet. Adware helps some developers recover programming development costs, and it may allow the software to be provided to the user of the application free of charge or at a reduced price: due to the advertising, the programmer may still profit from the wide use of their work, motivating them to write, maintain, and upgrade the software product. To prevent adware from being installed on your system, purchase and use full versions of software that are not supported by advertising. If you want to download and use software that claims to be free, carefully read the license agreement and cancel the installation if there is something that you do not understand or agree to. Know the software before you install it.