Adware infection

I'm getting a lot of pop-up ads randomly. They pop up almost every time I open a new window, regardless of which site I'm visiting. They play in the background. I can hear them but there's no window sometimes. Any help anyone can give me would be great!

My computer has Windows 7 and my virus protection is Microsoft Security Essentials. It's up to date and says my pc is clean.

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/512654/adware-infection/