LCD display flickrign problem. Urgent help required.

#include <reg51.h>
				   
sbit led=P0^0;

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

}

void main()
{
led=1;
delay(100);
led=0;
delay(100);

}

#define select P3

 sbit v28=select^4;
 sbit v14=select^6;
 sbit v7=select^5;
 sbit off=select^7;


	void switching() interrupt 0
		   {

					if(count==0)
						{
							 off=0;  v7=1; v28=0; v14=0;
							 count++;
						}
					else	
					if(count==1)	
						{ 
							v7=0; v14=1; v28=0; off=0; 
							count++;
						}
					else
					if(count==2)
					    {
							v14=0; v28=1; v7=0;  off=0; 
							 count++;
						}

					else
						{ 
						
							count=v28=v14=v7=0; off=1; 
							
						}



		   		/*  if(v28==0 && v14==0 && v7==0 && off==1)
				  		{ off=0;  v7=1; v28=0; v14=0; }
					
				    else
                        if(v28==0 && v14==0 && v7==1 && off==0)
                              { v7=0; v14=1; v28=0; off=0; }
					
					else
						if(v28==0 && v14==1 && v7==0 && off==0)
						      { v14=0; v28=1; v7=0;  off=0; }
					
					else
					   { v28=v14=v7=0; off=1; }	 */
						
		   
		   }