My macbook is about 4months old and never had problem browsing the internet. However since last night nearly every site i visit I get a popup stating the site certificate is not valid. Example: http://i42.tinypic.com/5v953p.jpg Now when I went onto mail it also says this also. http://i39.tinypic.com/qnpoiw.jpg Its come to the point Im tired of popups every 2minutes, I'm considering not using Safari even though I prefer it to other browsers. I'd really appreciate any help on this.