I've noticed a curious problem on the laptop I upgraded from Win8 to Win8.1 and then to Win10.
It seems after certain updates the task bar seems to not fully load and the start menu also doesnt load up either. I can still shut it down by right clicking on the start button and accessing that menu.
I usually end up opening cmd with admin privileges and typing;
dism /online /cleanup-image /scanhealth
dism /online /cleanup-image /restorehealth
Then reboot. So far everytime I've done this the task bar works again. I'm not sure why this works as it never shows up any errors.