If your system was shutting down properly before installing Norton A/V, go to www.aumha.org and go through the stpes of the W98 shutdown trouble shooting guide.
If it did have some problems before installing Norton, check the following:
1. IS power management enabled in BIOS settings?
Some motherboards will not shut down automaitically if Power Management is not enabled. Most AXT motherboards ignore shut down requests from the power button unless Power Management is enabled.
I have seen a couple of motherboards that had to have ACPI enabled in order to shut down automatically from Windows.
2. Are your motherboard (chipset) and video drivers up to date?
Video driver issues are the number 1 cause of W98 shutdown problems.
For a few video cards, I have had to update the video BIOS (from the card mfg) in order to correct shutdown problems.
Chas