Openload dot co Pop-Up Ads
If you suddenly start seeing advertising pop-ups you never saw before, as well as advertising injected into pages you browse, appearing in weird locations where there was none before, your system and favorite browser are very likely affected by a browser hijacker.
If the ads you see also have small-font text under them reading "Brought to you by Openload dot co" or "Ads by Openload dot co", you now even know the name of the browser hijacker in this specific case.
Browser hijackers are an extremely common form of potentially unwanted programs. The term "potentially unwanted program" refers to a number of application types that occupy the undefined space between legitimate software and full-blown, dangerous malware.
Similar to Openload dot co, browser hijackers can alter your browser's default home page and search engine, without ever asking for permission. They can then start displaying very intrusive ads that both slow down your browser and connection and can potentially lead to unsafe pages where you can get infected with more dangerous malware.
Some browser hijackers also have data interception and logging capabilities, recording your search queries and traffic and then selling them to third parties.
There is no surefire way to avoid similar potentially unwanted software entirely, but a good start would be to never trust websites that ask you to allow push notifications and to always download all your applications from reliable sources.
One very common propagation method for potentially unwanted programs are bundle installers. Those are software packages with multiple applications in them, some of which may be potentially unwanted. Similar installers can be found on some less reputable free download websites, which is why you should only use well-curated and safe download portals.