Remove "Security error detected Due to Suspicious Activity found on your computer" Pop-up – How to Block Fake Pop-up Alerts

I am tired of the pop up ads

Each time I open certain websites, a pop-up message shows on the webpage with message that
“Security error detected Due to Suspicious Activity found on your computer. Please contact Microsoft Certified Live Technicians For Help 1 855 757-2085”. I don’t know is it a truthful message or a scam, it looks like very legitimate. But I cannot stop those pop-up ads even though I tried many means to close the pop-up box. I am feeling very tired with those pop-up alerts.