spawnvp does not work

I wrote that program but spawnvp dows not call the exe files hello1,hello2!!!

#include <stdio.h>
#include <conio.h>
#include <process.h>

//Tv Rental system menu version 1
int user_selection();
void display_menu();
void call_program(int option,char *argv[]);
int main(int ,char *argv[])
{
int option;
do
{
display_menu();
option=user_selection();
if (option!=7) //Exit
call_program(option,argv);
}
while (option!=7);
return 0;
}


void display_menu()
{
clrscr();
printf("1 hello1");
printf("\n2 hello2");
printf("\n3 exit");
}

int user_selection()
{
int opt;
printf("\n Enter required option(1-3) : ");
scanf("%1d",&opt);
return (opt);
}

void call_program(int opt,char *argv[])
{
void delay();
switch(opt)
{
case 1:
spawnvp(0,"hello1.exe",argv);
delay();
break;
case 2:
spawnvp(0,"hello2.exe",argv);
delay();
break;
default:
printf("\n incoreect input");
delay();
exit(0);
}
}
void delay()
{
int i;
for (i=0;i<20000;i++);
}