I don't know about the different keys, but the whole hibernate thing and the icon highlighting deal is simple. . .
YOUR SHIFT KEY IS STUCK. Or at least, your keyboard is transmitting that your shift key is being pressed. Are any of the letters in your login or password capitalized? Maybe when you press that shift key, it gets stuck.
When you go to shut down your computer, hit the shift key and the standby turns to hibernate. This is by design and is working right.
When you hold down shift when clicking any icon, it thinks you are trying to select everthing from where the last highlighted item is to where you are clicking. Again, this is how it's supposed to work.