Pop-up ads

Hello,

My computer is suffering from an ad virus internet sites keep appearing
http://www212.paypopup http://z404

is there anyway of getting rid of it ...the computer is running very slow
I have tried to run Ad-Aware and Norton with no luck
Ad-Aware does not seem to be able to get rid of them

other sites that appear are:
www.health-yshopping
www.hug-ediscounts
www.ecommerc-e
www.dealiotoday
www.realcoupon

Would appreciate any help

Paul