In safe mode many programs don't run including avast (so you would have to have started it), so if there is any potential conflict it is likely not to appear. and you also mentioned something about your graphics card, that wouldn't be loaded either. So there is much less running on your system and much less stress.
Why it appears to go off when rebooting, I haven't the slightest idea (open applications, etc. are closed on system shut down so it may just be normal), but I would ask what is it doing open when rebooting ?
Run it again and post the complete reference to an invalid shortcut.
There are no icons in the system tray when the log viewer is open.
