keil 4 new project hex not working on board..

hi, i am using Keil 4 evaluation version for programming LPC2148. i wrote code for simple led blinking.when i creating new project and creating hex then this hex doesn't work on board. but when i compile same code on previously created project then it work fine. so what are the possible issue and what i have to do....my source code is as follows.....pls give me suggestions....

#include <lpc214x.h>
void delay(unsigned int n);
 void main(void)
{
        PINSEL0 = 0X00000000;
        IODIR1  = 0xFFFFFFFF;
        IODIR0  = 0xFFFFFFFF;
        while(1)
        {
         IOSET0 =0xFFFFFFFF;
         delay(1000);
         IOCLR0 =0xFFFFFFFF;
         delay(1000);
                }
}

 void delay(unsigned int n)
        {
                unsigned int i,j;
                for(i=0;i<n;i++)
                for(j=0;j<1275;j++);
        }