16x2 lcd not working

Hello..Im new to Arduino and now working for Arduino project.
I have problem on my lcd where when I running example of HelloWorld, only lights turn on but nothing appear on the screen.
I have no idea whether Im using the wrong library or anything wrong with my connection. For information, Im using LiquidCrystal library and I follow tutorial from Arduino Tutorial - connecting a parallel LCD.

Thanks for any help

should I change the library or any suggestion for the trouble?

Im using LiquidCrystal library and I follow tutorial from Arduino Tutorial - connecting a parallel LCD.

About halfway through that tutorial there is a section called "Bus wiring". Just above that point is a photograph. Have you been able to get your display to look like the one in that photo? By the way the LCD in that picture is upside down, it is the top row that has the dark rectangles.

Don

the lcd already working..after checked for several times, there are error in connecting the pins (there are some pins of arduino that connect to wrong lcd pins).