I have Norton Anti-Virus 2008. I conducted a scan and found a trojan in my external harddrive called trojan.brisv.A!inf with some mp3 files. I tried to delete the file and the containing folder but I couldn’t. It asked me for permission and told me to try again. I tried to quarantine and remove it with Norton but it didn’t work. What do I need to do to get rid of this trojan?