A name and if possible a path for the trojan would help. Have you tried Googling the name?
Please include the following information:
What is your operating system, service pack and are you up to date with Microsoft update? There are two ways of checking this. Go to Start/Run and type in winver then click the Enter key. Or, right-click My Computer in the Start Menu or on your desktop (or Computer in Vista) and select Properties. Post what it says.
What McAfee products do you have? Right-click the taskbar icon and select Open SecurityCenter and then click "View Details" or "About" at the lower right of the new window. Post the details from each module.