Trojan.gen.2 Trojan.zeroaccess virus

My computer is infected by trojan.gen.2 and trojan.zeroaccess.  Everytime I boot up the computer, Norton will find the virus and quarantine it and tell me I need to reboot to resolve the problem, but the same thing happens everytime I reboot.  I would appreciate some help when Quads is available.  I am running Windows Vista 64 bit and I have a flash drive.  Thanks.