mal ware help?

Hi, im having a lot of pop ups coming up saying “threat has been detected” every minute pretty much with 2 different sites. these sites i have never been on, or dont even know what they are. It starts once i open up my computer, and even when i am not on the internet or on any sites at all, so i dont get how this threat is been detected. It also happens when im on site suchs as facebook and banking sites and its not even the site named on the pop up. what is this and how can i fix it.

Thanks.

Could you follow the steps here http://forum.avast.com/index.php?topic=53253.0

And attach the logs in this thread