How to change your grades is actually really low-tech but would
  get you in heaps of trouble when they see you on camera doing
  it...

  1) find out who has the power to change your grades

  2) Find their password (it's usually hiding under their
  keyboard, or top drawer - that's where 80% of people write down
  their passwords)

  3) when they're out to lunch, login and change your grades.

  But I don't recommend it because a) security cameras are
  everywhere and disabling them is a whole diff story b) There
  will be multiple passwords: unlock screensaver, login to the
  network, to open up the software and to change the grades. It
  might not be that many but it'll be at least 2 passwords you'll
  have to find and get right - AND username too. And the
  punishment would be too severe.

  But it's technicallly possible.

  Probably can't do it from home because : they won't let grade
  changing happen from computers outside the school LAN -you're
  not the first person to want to change their grade... and many
  try :)

  But if nothing else, the #1 hacking tip is this: psychology and
  behavior. People keep their passwords under their keyboard or in
  the top drawer of their desk or somewhere they can find it
  easily. Sit down in their chair and reach around. If they have
  it written down, it'll be something you can grab with your hand
  from the chair.

  a) people are lazy and don't want to stand up

  b) they write down the password because the network
  administrators often set it up where they have to change their
  password every 30 days/90 days/whatever and people can't
  remember new passwords so they write them down.

  That's the funny part: They think they're making it more secure
  by forcing the secretaries and princpal and stuff to change
  their passwords a lot. But they're making it worse because then
  the people have to write it down - and every body thinks ''under
  the keyboard'' is original. It's not :) Enjoy the hacking tip :)