There is ads ALL OVER every webpage I go to and I don't know why!?

[Woah]

On my Facebook in the middle of scrolling down an add comes out of no where and there is always a random ad on the bottom of my picture and twitter, YouTube, yahoo, tumblr you name it random ads on the top of the page and also while scrolling random ads just pop up in the middle of the screen. I tried to do what people say go to the toolbar, block the ads on Chrome and such, but nothing works, On my Firefox and Internet Explorer too!!

These are not normal ads that you usually see, and they were NEVER here until now. I have been using these sights for years and never had these problems until about 3 months now and it driving me CRAZZYY! and I know these Ads are not sponsored through the websites, it has to be something else. I have not downloaded any random thing either.
Even words are HIGHLIGHTED and if you hover it it wants to take you to some website that has nothing to do with the word??


This has happened ever since my Trenton Security expired so
Now I have AVG (free) and I run tests but say no threats are nothing found what do I do!? Please!