Q: Where can I get the Computer Upgrade?
A: There is none.

Q: How can I get to the library?
A: Hit '+' at StarDock.

Q: What good is a ship password?
A: Two things. 1) To keep your own corp. members out of your ship. 2) If you invade a planet and there are people in the citadel with tradable ships (and you're in a tradable ship you'll be able to get their ships. This will give them useless ships in return. You can then use them yourself with all fighters and goodies intact or else sell them at the stardock. If other traders have their passwords set, you'll have to either evict them or just blow them up with the planet. You will not be able to trade their ships.