请问我如何能够使用root用户？

我在win2k上安装cygwin1.5.9-1，以IanJing（管理员）登录windows，启动cygwin后，使用
$ su
su: user root does not exist


/ect/passwd内容如下：
SYSTEM:*:18:544:,S-1-5-18::
Administrators:*:544:544:,S-1-5-32-544::
Administrator:unused_by_nt/2000/xp:500:513:U-JIANG\Administrator,S-1-5-21-1214440339-1677128483-854245398-500:/home/Administrator:/bin/bash
Guest:unused_by_nt/2000/xp:501:513:U-JIANG\Guest,S-1-5-21-1214440339-1677128483-854245398-501:/home/Guest:/bin/bash
IanJiang:unused_by_nt/2000/xp:1003:513:IanJiang,U-JIANG\IanJiang,S-1-5-21-1214440339-1677128483-854245398-1003:/home/IanJiang:/bin/bash
VUSR_DSP007:unused_by_nt/2000/xp:1000:513:VSA Server Account,U-JIANG\VUSR_DSP007,S-1-5-21-1214440339-1677128483-854245398-1000:/home/VUSR_DSP007:/bin/bash

我试图在/ect/passwd的第一行增加
root:*:0:0:root:/root:/bin/bash

则
$su
Password:
su: incorrect password
--
FROM 159.226.40.*