Turn off automatic updating for norton live if you can I suppose. Its probably doing updates and forcing a reboot for some reason. Thats just a guess though based on what you said. Im not sure if any program has the ability to restart with out user input or not. Id assume it can be done but is bad practice with out a user confirmation.
Here's an idea. Turn off hibernate. Microsoft has never been able to get hibernation to work properly. The nickname of hibernate is "coma mode", because the computer often times has issues restarting after hibernating, sluggish performance after restarting, or shutting down after restarting (as in your case). Sleep mode is MUCH, MUCH better to put your computer into, rather than hibernation. Granted, it uses more power since the computer never completely shuts down (the memory continues to have power going to it to keep the computer ready to restart at a moments notice, but the processor, HDD & monitor shut down).
Go into the control panel < power options, then set everything to "sleep" or "do nothing". If any say "hibernate", change it. This will save you the headache of having coma mode issues.