You havent been hacked, you have a spam issue with your browser and its telling you theres an error so that it can get you to then click a certain box within the application giving the messages. Anytime your internet browser tells you anything thats related to the security status of your computer, do not believe what it is telling you and do not click anything it asks for you to click, dont even click the X button if one appears as an option with any of the messeges you happen to recieve. Just close the browser entirely with task manager or resource monitor. You need to reset the web browser. I reccomend you use chrome and when you have these issues go into chrome settings and type reset then click the button and it will remove the spam causing issues.