Norton keeps blocking 80000032.@ trojan.gen 2 and 80000000.@ hacktool.rootkit

Hi, i am having a serious problem with a virus on my computer. I have Norton anti virus 2012 and two trojans   called 80000000.@ hacktool.rootkit and 80000032.@ trojan.gen 2 keeps attacking my computer no matter how many times it is blocked. It seems as f norton is not able to get rid of the virus therefore it always reappears. Is anyone aware of why this happening so that I can fix my computer? Thank you.