processes just dying after 2 or 3 weeks

We have a simple little scheduling program,
that runs in background but we find it stops unexplainably after 2 or 3
weeks, intermittedly on all Windows platforms.
How can the operating system stop this process?

We are bereft of ideas.

Regards,

Robert.

The Code is as simple as the below, TScheduleThread is a simple TThread
object.

program basxScheduler;

uses
  Forms,
  Windows,
  dmScheduler in 'dmScheduler.pas' {datScheduler: TDataModule};

{$R *.res}

begin
  Application.Initialize;
  Application.Title := 'BasX Scheduler';
  Application.CreateForm(TdatScheduler, datScheduler);
  Application.Run;
  datScheduler.RunScheduleEvent;
end.

procedure TdatScheduler.RunScheduleEvent;
var
  ScheduleThread : TScheduleThread;

begin
  ScheduleThread := TScheduleThread.Create;
  ScheduleThread.Resume;
  ScheduleThread.WaitFor;
  FreeAndNil(ScheduleThread);
end;

procedure TScheduleThread.Execute;
begin
  while( not Application.Terminated )or
       ( Terminated )do
    begin
      RunScheduleEvent;
      sleep(10000);
    end;
end;