Pop-Up spyware?

[Mockery]

So I was doing a search on google yesterday and when I loaded one of the pages that came up, it tried loading all sorts of shit. Fortunately, most of it was blocked... but I do believe some spyware got through. Because ever since then, I've been having pop-up ads appearing randomly in places where they just shouldn't be appearing.

Like when I go to livejournal or google, I'll sometimes get pop-ups now. And those sites never have pop-ups.

Now I ran Lavasoft's Ad-aware afterwards, but it didn't seem to find anything new. Any suggestions on how I can find what's causing this annoyance?