Yes your AV should take care of them as long as it it updated. A trojan refers to the trojan horse where it comes in looking like somthing innocent and there is something bad inside. The something here is a virus most likely. The popup you are getting are trying to get you to pay for software to get rid of things on your computer that may or may not be there. You have spyware on your computer. You should get a cleaner for it. Lavasoft has one called Ad-Aware. It is free and will clean these things off of your computer. I would get someone who knows about these things to help you though. It is not complicated but things can go wrong.