Mega 1280 upload problem

Assistance please!!
I uploaded asketch a few days ago successfully but now get the following sync error message when I try to load any sketch:
"
Problem uploading to Board
Binary sketch size: 2670 bytes (of a 126976 byte maximum)
avrdude: stk500_getsync(): not in sync: resp=0x30
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x51
"

My Sketch is for a graphic LCD screen as follows (the red led blinks about oncea second, indicating the sketch is running):
Any clues onhow to fix this

/*Example initialization with custom control pins */
#include <S1D13700.h>
/*create our S1D13700 LCD object and name it
glcd. */
S1D13700 glcd;
void setup() {
/Specify control pin connections/
glcd.pins.rd = 36;
glcd.pins.wr = 34;
glcd.pins.a0 = 32;
glcd.pins.cs = 30;
glcd.pins.rst = 33;
/*Call the setup routine */
glcd.initLCD();
/*Create a string variable */
char buf[] = "Hello World!";
/*Clear the screen */
glcd.clearText();
glcd.clearGraphic();
/*specify the column and row address
where the text should be output */
glcd.textGoTo(10,1);
/*Write our string variable to the screen */
glcd.writeText(buf);
}
void loop()
{

/*Blink the LED for verification that
the program is executing succesfully */
pinMode(13,OUTPUT);
while(1)
{

digitalWrite(13,1);
delay(500);
digitalWrite(13,0);
delay(500);

}
}

(deleted)

Hi,
Thanks for quick response
I have already tried that - same result on the 2 available (com 3 & 4). Also checked the correct board was selected and re-starting the IDE with Arduino attached.

Should have also added the Header file includes the following to enable Port A to be used by the graphic LCD display
//#define S1D13700_CUSTOM_DATA_PINS
#define FIXED_DIR DDRA
#define FIXED_PORT PORTA
#define FIXED_PIN PINA

Randal