Zango, an online advertising company, is to pay $3 million for "unfairly and deceptively" downloading adware onto people's computers.
The Federal Trade Commission (FTC) agreed to settle with the company after claiming that it installed 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 uninstall utility to help recipients remove the software.
The FTC said the firm used third parties to install adware onto PCs, concealing the programs in screensavers, browser updates or free games.
The applications then monitored the consumer's internet use and presented pop-up ads based on data gathered from the adware.
The FTC claims that 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," she said.
Keith Smith, Zango CEO, apologized for the adware downloads: "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," he said. "We deeply regret and apologize 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."