Safari/Firefox on Imac keeps crashing, I hear this is happening to many!

So out of know place 2 days ago any website(so it seems) that used flash, example a myspace with a flash music player will load and then I get that spinning pinwheel. It never goes aware I have to force quiet out of the browser. This happens in Firefox and Safari. I downloaded the latest everything, flash, browsers, all OS updates. This is still happening and Apple wants $150 to tell me what’s wrong. I looked it up online and saw ALOT of people having the same issue especially they they go to ESPN.com Anyone know the fix?