Seriously...can NOT get rid of this stupid malware "Coupon Giant" thing...and it keeps popping (or pooping) up ads on my computer and I think it's grinding my pc to a slow crawl. How do I get this off my computer?

I've got superantispyware running, and malwarebytes (both the free version)...do I need to just bite the bullet and buy the full blown software because I'm only getting the "light" version?

GAH!