using adaware

Just want to ask when i had the free version of adaware it seemed to help out alot. Now i am not a computer whiz by no means, and i only understand layman's terms. But can someone tell me when you use it and delete or quaranteen those bad ones, why do i get messages then saying that i can't run something? How would i "clean" it so that i can use it, without paying money for the service? Sorry i am probably asking dumb questions, but that's me and computers. I keep getting alot of pop ups that won't stop no matter what i have on here.