Problem with interrupt response to input from magnetic sensor

Hi,

I have interfaced a G2553 with a magnetic sensor on the P2.0 port. Whenever I single step and bring a magnet in close proximity to the magnetic sensor the port 2 ISR executes perfectly.

But when I run the program and bring the magnet close to the magnetic sensor the program does enter the ISR at all.

void main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop watchdog timer

P1DIR |= BIT6;
P1OUT &= ~BIT6;
LCD_init();
P2DIR=0xFE;
P2OUT=0x00;

P2REN|=BIT0;

LCD_clearScreen();
for(i=0;i<2;i++)
{
LCD_clearScreen();
__delay_cycles(1000000);
LCD_setCursorPosition(0,5);
LCD_printStr("SASTRA");
LCD_setCursorPosition(1,2);
LCD_printStr("Racing");
LCD_setCursorPosition(1,9);
LCD_printStr("Team");
__delay_cycles(1000000);
}

LCD_clearScreen();
LCD_setCursorPosition(0,0);
LCD_printStr("Initializing");
for(i=0;i<20;i++)
{
LCD_printStr(".");
__delay_cycles(100000);
if(i==3)
LCD_setCursorPosition(1,0);
}
LCD_clearScreen();

//******************ADC setup***************
ADC10CTL0 |= ADC10ON; //switching on ADC
ADC10CTL1 |= INCH_7|ADC10DIV0|ADC10SSEL_1|CONSEQ_0; //assigning P1.0 to ADC
ADC10AE0 |= BIT7 ; //enabling analog channel A0
ADC10CTL0 |= ENC|ADC10SC; //enabling conversion and starting

//******************Timer setup*************
TA1CCTL0 = CCIE;
TA1CTL = TASSEL_2|ID_3|MC_1; //selecting a presclar of 8 to get 125kHz clock
TA1CCR0 = 0xFFFF; //loading a count value of 62500 which when run two time will produce a delay of 1s

P2IE|=BIT0; //enabling port pin interrupt for resetting the odometer count
P2IES=1;
P2IFG &= ~BIT0;

__enable_interrupt();

while(1)
{
LCD_clearScreen();
ADC10CTL0 |= ENC|ADC10SC; //enabling conversion and starting
temperature=(ADC10MEM*35)/100;
__no_operation();
LCD_setCursorPosition(0,0); //forcing cursor to the 1,1
LCD_printStr("Temp:");
convert_temperature(temperature);
temperature=0;
LCD_setCursorPosition(0,10);
convert_distance(distance);
LCD_setCursorPosition(1,0);
LCD_printStr("Speed:");
convert_speed(speed);
__delay_cycles(505000);
}
}

#pragma vector=PORT2_VECTOR
__interrupt void reed_switch(void)
{
LCD_clearScreen();
LCD_printStr("success");
__delay_cycles(100000);
P2IFG &= ~BIT0;
}

Kindly help me 

Thank You