After running a manual full system scan on my internal HD with NAV my display would not respond to input from key board or mouse and remained in 'display sleep' forcing a nasty manual shutdown which in turn produced a kernel panic. Activity log showed the scan as 'No problems found'. No other programs were running during the scan. This is the first such incident in three years on this computer.
If you need more info, please advice. I did search the console logs but found only the kernel panic triggered apparently by the power button shutdown.
Intel OS X 10.4.11 (2007) 2GB RAM
Fully updated NAV 11.1.1,1.30,5.1.1