Hi, Don..
Thanks so much for all of your advice. I only have Norton Internet Security 3.0.3 installed--not Norton Utilities, which seems to be causing most of the problems with other users' computers. I am running Panther which is not as good as Tiger when it comes to the OS firewall. I am avoiding upgrading to Tiger because then I will probably face a whole new range of other problems! I have Cocktail, which I set up to run once a week, and Disk Warrior (which I have never used). I will have to carefully read the link on maintenance and follow-through on backups, etc.
Thanks again. I apprec iate your taking the time to reply to my post.
Marilyn