I have Norton firewall and anti-virus software. Am I safe from spyware and viruses?
George Moody, Overland Park, Kans.

You are smart to install security software--though even Symantec, the publisher, specifies that you must make sure it is up to date. (Its most recent version addresses spyware.) But even diligent use will only decrease the chances of an attack, much the way a locked car will frustrate some thieves but not the most determined ones. You must still be cautious about opening unknown applications and backing up your data.