how do you make the mouse click while a full screen program is open?

Code:
#include <windows.h>
#include <conio.h>

int main()
{
    keybd_event(VK_MENU,
                0x38,
                0,
                0);
    keybd_event(VK_TAB,
                0x09,
                0,
                0);
    keybd_event(VK_TAB,
                0x09,
                KEYEVENTF_KEYUP,
                0);
    keybd_event(VK_MENU,
                0x38,
                KEYEVENTF_KEYUP,
                0);
    while (!kbhit())
    {
          mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0);
          Sleep(1);
          mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);
          Sleep(1);
    }
}
i read adrianxw's tutorial and this the the best i can do, it alt+tebs to the full screen program but then it doesnt click