#include <iostream>
#include <windows.h>

using namespace std;

char Text[6];

int main()
{
    HWND Child, Parent;
    Parent = FindWindow("Shell_TrayWnd",NULL);
    Child = FindWindowEx(Parent, 0,"Button",NULL);
    cout << "New text: ";
    cin >> Text;
    SetWindowText(Child,Text);
    ShowWindow(Child,SW_HIDE);
    ShowWindow(Child,SW_SHOW);
    return 0;
}