automated mouse clicks make screen go blank - c++

Question

I am working on writing a program that will do a few mouse clicks for me in a loop. I created a struct and set it to type INPUT_MOUSE to replicate the clicks and used SendInput() to send the info. everything compiles right and could be called a "working" program but I ran into a rather funny glitch. I wrote the program on my laptop (windows vista) tried it and it worked fine. When I rewrote the same exact code and used it on my desktop (Windows 7) when I run the program my screen will go to black as soon as I start the automation part of the program just like it does when it goes into sleep mode. The program will run in the background just fine, but its kind of a pain that the automater blacks my screen out. What is going on here?
I am adding my code:
#include "stdafx.h"
#include <windows.h>
#include <iostream>
#include <string>
#include <time.h>
using namespace std;
void clicky(int x, int y)
{
// 5 sec wait
clock_t run;
run = clock()+5*CLOCKS_PER_SEC;
while (clock() < run) {}
//plug in cursor coords and click down and up
SetCursorPos(x,y);
INPUT mouse;
mouse.type = INPUT_MOUSE;
mouse.mi.dwFlags = MOUSEEVENTF_LEFTDOWN;
SendInput(1,&mouse,sizeof(INPUT));
mouse.type = INPUT_MOUSE;
mouse.mi.dwFlags= MOUSEEVENTF_LEFTUP;
SendInput(1,&mouse,sizeof(INPUT));
}
void main()
{
int coords=0;
string h;
//find out how many clicks are needed
cout << "How many clicks will you need?";
cin >> coords;
//extra getline here without it when return is hit
//from entering the click amount it would also enter
//a cursor coordinate
getline(cin,h);
POINT p[21];
for (int count = 1;count<=coords;count++)
{
cout << "Place mouse cursor where you want a click and press return"<<endl;
//each time return is hit the cursor coordinates
//will be stored in the corresponding spot in
// the p array
string key = "r";
getline(cin,key);
GetCursorPos(&p[count]);
break;
}
string go;
cout << "Hit Return to initialize your click loop";
getline(cin,go);
while (true)
//infinite loop cycling through the users
//cursor coordinates and clicking
{
for(int click=1;click<=coords;click++)
{
int x = p[click].x;
int y = p[click].y;
clicky(x,y);
}
}
}

Answer 1

Try initializing the INPUT structure to all zeroes before calling SendInput(), like
INPUT i;
ZeroMemory(&i, sizeof(i));
In addition to that, make sure that the coordinates you specify are not too large.
I had the screen go blank (in fact, the screensaver kicked in) when doing either of these two wrong.