Have trojan need fix

I am running WinXP home edition. I have downloaded AVG free edition and it has detected 6 trojans in my system volume information file and gives me some long file number I don't understand. How do I find the program to remove the trojan. I tried using the run dialog box but I get the message "could not find". what do I do now? I have tried everything I know. AVG say the program cannot be removed that the entire file has to be deleted. If this is so will it affect my operating system? How can I get rid of it without damaging my OS?

Brian