On the main menu, up the top of the screen, go to Instant Action and down near the Star Wars Battlefront 2 logo, on the left side of the screen, down the bottom left that is, is the logo. Put your mouse cursor just on the bit of logo and click once, then type. It should work. Here are the codes...

mostimpressive - invincible
agoodblasteratyourside - infinite ammo
usetheforceluke - no hud
456123 - all campaigne maps unlocked

~~Glitch Master Ember