How Can I Get Rid Of This Antivirus

i have just noticed that there has been an attack on my system,i suppose it's a trojan horse i.e someone trying to hack into my system.i am connected to the net via starcooms & it comes up from 6pm to 11pm,i wuldnt mind if someone culd help me out with a probable & secured solution.so many pop ups and cookies keep coming on despite me using a pop-up blocker.please help out.