How to stop an announcement from a Trojan found several weeks ago on a CD?

Hi, 

I’m using Norton Internet security 2009. Several weeks ago Norton detected on a CD from a friend a Trojan. The Trojan could not be removed.  Now I get at start up a message that Norton has found a Trojan and suppose me to do another scan to remove it on d:.  But as het detected the Trojan on a cd, the Trojan was never installed on the harddisk.  I cleaned the history; but the message keeps coming. How can I stop this disturbing warnings. Thank you for any possible solution,Patrick