Q: pop up ads

all of a sudden I get all these pop up ads for mac cleaner, to create my own wed site, to take an online survey to win a free iPhone, or to create an account to stream free movies. I had tried everything to get them to stop i restarted my safari browser, create a new gmail account, i blocked all pop up ads to show up, I have even tried using different browsers such as google chrome and firefox but nothing works. This is making me not wanna use my computer anymore and it gets annoying when i have to keep exiting all these ads just to get to the site i am trying to use. Please help me try to fix my computer i have only had it for about a year.