digitalWrite(LED,HIGH) and digitalWrite(LED,LOW) dont work?

Hi guys,

I am very new on Arduino. I did a test to blink a LED. The problem was the voltages of digitalWrite(LED,HIGH) and digitalWrite(LED,LOW) were similar, about 2,1v. But on the arduino page it says 5v for digitalWrite(LED,HIGH) and 0v for digitalWrite(LED,LOW).
i also had a 330 ohm resistor conected pin 9. does anyone help me?
here my code:
#define LED 9
void setup()
{
pinMode(LED, OUTPUT);
}
void loop()
{
digitalWrite(LED,HIGH);
delay(1000);
digitalWrite(LED,LOW);
delay(1000);
}

If you change to pin 13 and the on-board LED blinks then it's your wiring.

I've tried to use pin 13, but it did not work, and the tiny led on the arduino board turned off. I don't understand why

byte LED = 13;
void setup()
{
  pinMode(LED, OUTPUT); 
}
void loop()
{
  digitalWrite(LED,HIGH);
  delay(1000);
  digitalWrite(LED,LOW);
  delay(1000);
}

thank you Runaway Pancake,
I realize that, my real problem is not my code or my wiring. It is that arduino chip, i can not upload new programs into the chip, even my RX and TX blink, it seems that my old program still be in the chip.
I dont know how to reset RX and TX to be able to put my new program into the chip.

Shouldn't make a difference anyway.
Say you used pins 0,1 as general purpose I/O, they'd still be used during an upload (assuming nothing else is connected to them and the USB link and everything else in between is OK.)
Pins 0,1 can be used for general purpose I/O, but whatever is connected to them should be disconnected during an upload.

Is LED one of the special key words?
Try changing the name to ledPin or something besides LED.

Did you get the drivers installed for the USB/Serial chip on your board?
If you open Control Panel/Device Manager/Ports, do you see the port you are using with No exclamation point over it?
Mac/linux, I don't what know the similar thing is.

CrossRoads:
Is LED one of the special key words?
Try changing the name to ledPin or something besides LED.

What I posted works for me.
(I made sure to compile and upload that, it was at/near my bedtime.)