Online advertising company, Zango, is to pay $3 million (£2 million) for "unfairly and deceptively" downloading adware onto people's computers.
The US based business was fined by the Federal Trade Commission (FTC) after installing adware more than 70 million times, causing 6.9 billion pop-up ads.
According to the settlement, Zango is barred from downloading adware without the user's consent and is required to provide an uninstalling utility to help recipients remove the software.
The FTC alleged the firm used third parties to install its adware onto user's PCs, concealing the programs in screensavers, browser updates or games being offered for free.
The applications then monitored the consumer's internet use and presented pop-up ads based on data gathered from the adware.
The FTC claim Zango - previously called 180 Solutions - made the software difficult to identify, locate and remove once it was installed.
Lydia Parnes, Director of the FTC's Bureau of Consumer Protection said: "Consumer's computers belong to them, and they shouldn't have to accept any content they don't want.
"If consumers choose to receive pop-up ads, so be it. But it violates federal law to secretly install software that forces consumers to get pop-ups that disrupt their computer use."
Keith Smith, CEO of Zango, said: "We relied too heavily on our affiliates to enforce our customer notice and consent policies.
"Unfortunately, this allowed deceptive third parties to exploit our system to the detriment of consumers, our advertisers, and our publishing partners. We deeply regret and apologise for the resulting negative impact."
He added that Zango would "embrace the new standards" required by the FTC and "continue to create, abide by and strive for best practices that protect consumers."