If the answer to any of the following questions is “NO,” that means your computer is infected with Fireball or a similar adware.
Open your web browser and check:
- Did you set your homepage?
- Are you able to modify your browser’s homepage?
- Are you familiar with your default search engine and can modify that as well?
- Do you remember installing all of your browser extensions?
To remove the adware, just uninstall the respective application from your computer (or use an adware cleaner software) and then restore/reset your browser configurations to default settings.
The primary way to prevent such infections is to be very careful when you agree to install.
You should always pay attention when installing software, as software installers usually include optional installs. Opt for custom installation and then de-select anything that is unnecessary or unfamiliar.