There's something wrong with my computer?

So I'll search something on google like song lyrics, information on something i want to learn about, a store, whatever. The results come up normally, the website will be like "hottopic.com" or "lyricsmania.com' but when i click on it, it redirects to some site trying to sell me something, or worse, some creepy porn site. Then I click back and click the link again, and it goes to the site i was trying to go to. I haven't been on any questionable sites and I've run several virus scanners and deleted all threats. But this still continues. What can I do to fix it?? (In English please. I don't speak computer geek :P)