It seems like you are dealing with adware. Malware designed to create traffic to dangerous websites. Usually, it installs rogue programs or add-ons to your browser. Let's check that first. Look in your browser add-ons if you have any extensions that you do not recognize or haven't used for a while, remove them.
Do your other browsers have it? It could be system wide, in which case I would recommend looking at your installed apps/programs and see if there is something that you don't recognize. If there is, remove them. After you confirm or deny of such software/add-ons, scan your PC with previously mentioned Malwarebytes and Hitman Pro, these two software's should deal with most of the malicious issues. Additionally, you can scan your PC with any anti-virus software of your choice just to be sure.
For future reference, you can install an Adblock in your browser to prevent malicious infections through ads. Good luck!