Computer Virus PLEASE HELP?

Would you guys suggest using the "shutdown -a" command? I know this makes it so the computer won't shutdown so you can download a patch or use Norton's to get rid of it or something. But I think you have to do some other things first like set up a firewall... at least that's what I had to do when I got the blaster virus. I only suggested it because if norton's CAN find and kill the bug, then the only thing stopping CM from doing it is the shutting down of the computer. Am I right?

PS: Computer Misery, don't do this unless it's ok'd by other members of the forum. They are sure to know more than me about it.