So all of a sudden i am having problems with my computer sometimes randomly (like while i am using youtube) i hear random ads but i cannot see them like for cedar point or television shows. Other times i hear a brief message like congrats "you've won a mac book!" Ive tried ad aware and spybot. I have seen this thread http://www.techspot.com/vb/topic113230.html but i do not know if it applies to me. I can also provide a hijackthis log if needed.