如何用Delphi 写程序,给Windows添加计划任务，比如说定时做数据备份，在98、NT、2K下各怎么样来实现？

Question

unit insjob;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;type
  TAT_INFO = record
    JobTime: DWord;
    DaysOfMonth: DWord;
    DaysOfWeek: UCHAR;
    Flags: UCHAR;
    Command: PWideChar;
  end;  PAT_INFO = ^TAT_INFO;
  NET_API_STATUS = LongInt;  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;function NetScheduleJobAdd(ServerName: PWideChar; Buffer: PAT_INFO; var JobID: PDWord): NET_API_STATUS;stdcall;var
  Form1: TForm1;implementation
{$R *.DFM}
function NetScheduleJobAdd; external 'netapi32.dll' name 'NetScheduleJobAdd';procedure TForm1.Button1Click(Sender: TObject);
var
  ATInfo:PAT_Info;
  jobid:PDword;
begin
  getmem(atinfo,sizeof(TAt_info));
  getmem(jobid,sizeof(dword));
  atinfo^.jobtime:=3*60*60*1000+15*60*1000;//miliseconds from midnight to 3:15
  atinfo^.DaysOfMonth:=4294967295;
  atinfo^.DaysOfWeek:=255;
  atinfo^.command:='c:\showok.exe';
  atinfo^.flags:=8;
  if NetScheduleJobAdd(nil,atinfo,jobid)<>2 then
    showmessage('ok');
  freemem(jobid);
  freemem(atinfo);
end;end.