Hi I've had a MacBook Pro for almost ten years, but started to slow up once I updated the operating system. So I bought a MacBook Air which is great, last night I tried to install some software using a YouTube video as a guild & I now keep getting loads of stupid ads over some of my pages. I was going to install Vuze software but when I saw all the Mackeeper ads etc I decided not to install, but I've got the stupid ads. Does anyone know where these are stored & how to remove them. Thanks.