PS - Yes/No Timer

INT_PTR CALLBACK Timer(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    int counter = 0, choice = 0;
    static int step = 1;
    BOOL* LPt = NULL;
    BOOL SIG = TRUE;
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        SendDlgItemMessage(hDlg, IDC_PROGRESS1, PBM_SETRANGE, 0, MAKELPARAM(0, 100));
        SendDlgItemMessage(hDlg, IDC_PROGRESS1, PBM_SETSTEP, step, 0);
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        else if (LOWORD(wParam) == IDC_BUTTON1)
        {
            SetTimer(hDlg, TIMER1, 20, NULL);
        }
        break;

    case WM_TIMER:
        if (GetDlgItemInt(hDlg, IDC_EDIT1, LPt, SIG) == 100)
        {
            KillTimer(hDlg, TIMER1);
            choice = MessageBox(hDlg, "ДА спре ли таймера?", "Избор", MB_YESNO);
            switch (choice)
            {
            case IDYES:
                EndDialog(hDlg, LOWORD(wParam));
                break;
            case IDNO:
                counter = 0;
                SetDlgItemInt(hDlg, IDC_EDIT1, counter, SIG);
                SendDlgItemMessage(hDlg, IDC_PROGRESS1, PBM_SETPOS, 0, 0);
                SetTimer(hDlg, TIMER1, 20, NULL);
                break;
            }
        }
        else
        {
            counter = GetDlgItemInt(hDlg, IDC_EDIT1, LPt, SIG);
            counter++;
            SetDlgItemInt(hDlg, IDC_EDIT1, counter, SIG);
            if (SendDlgItemMessage(hDlg, IDC_PROGRESS1, PBM_GETPOS, 0, 0) < 100)
            {
                SendDlgItemMessage(hDlg, IDC_PROGRESS1, PBM_STEPIT, 0, 0);
            }
        }
        break;
    }
    return (INT_PTR)FALSE;
}