I installed a new hd in my macbook pro late 2011 a few months ago and soon started getting lots of ads plastered all over things I was reading. Upon support inquiry, I was advised, among other things, to try this:https://adblockplus.org/ and it worked great until recently. Now I'm getting the same kinds of ads again. I tried isntalling that again to no avail. The ads all have a little x beside a right facing triangle (arrow) in top right corner. How can I get rid of all these ads?