I have Norton's Systemworks2002 and Norton's Firewall. I really don't have a clue what a .dat is (I assume a data file, but am probably wrong). I DO have Norton's subscription service and receive automatic updates on viruses, etc. It automatically scans on a weekly basis. I do run Disk Doctor frequently and always have registry errors when I run Windows Doctor and they get deleted at that time. A lot of the little things come from having a dial-up connection as opposed to DSL. Compounding the problem is that I have AOHell and that bounces me on its own with its "ABSyncError" messages. Someone is coming over in a couple of weeks to look at how Windows was installed to see what's causing the registry errors and that will hopefully make that annoyance go away. Thank you for taking the time to post this info. I've printed it and will show it to the pc guru when he comes over. Andy is right when he says if you have the software and don't use it, you may as well not have it at all.