getting data to show on Liquid Crystal LCD 4x20

have the arduino cookbook, wired the screen all together with the Arduino Uno and a breadboard...

initially we had question marks and a sideways H show in the first row and first four columns. We've rewired it and now it won't show data at all.

The screen's backlight is now always on but not printing the command. Can I bypass the LiquidCrystal.h library or should I leave in the reference?

This is small piece to a larger project, I just want to control what's displayed on the screen and run a simple test of having it print, "hello world"

Is your LCD compatible with the library (HD44870 or something like that) ?
Can you post a link to the datasheet?
Can you post your code used?
Can you post the schematic?

Lot of questions, but we need as much info as possible to give you the best help we can :wink: