CentOS network interface can not start because two network manager are enabled

Not sure why this happen on my machine. It is probably because of installing software. Anyway, below is the error message I saw when this happened. And commands to switch off one network manager.

[yiyujia@localhost ~]$ su
Password: 
[root@localhost yiyujia]# service network start
Bringing up loopback interface:                            [  OK  ]
Bringing up interface eth0:  Active connection state: activating
Active connection path: /org/freedesktop/NetworkManager/ActiveConnection/5
Error: Timeout 90 sec expired.
                                                           [FAILED]
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
RTNETLINK answers: File exists
[root@localhost yiyujia]# chkconfig --list | grep -i netw
NetworkManager  0:off 1:off 2:on 3:on 4:on 5:on 6:off
network         0:off 1:off 2:on 3:on 4:on 5:on 6:off
[root@localhost yiyujia]# chkconfig NetworkManager off
[root@localhost yiyujia]# chkconfig --list | grep -i netw
NetworkManager  0:off 1:off 2:off 3:off 4:off 5:off 6:off
network         0:off 1:off 2:on 3:on 4:on 5:on 6:off
[root@localhost yiyujia]# service NetworkManager stop
Stopping NetworkManager daemon:                            [  OK  ]
[root@localhost yiyujia]# chkcofnig network off
bash: chkcofnig: command not found
[root@localhost yiyujia]# chkconfig network off
[root@localhost yiyujia]# service network stop
Shutting down interface eth0:                              [  OK  ]
Shutting down loopback interface:                          [  OK  ]
[root@localhost yiyujia]# chkconfig NetworkManager on
[root@localhost yiyujia]# service NetworkManager start
Setting network parameters...                              [  OK  ]
Starting NetworkManager daemon:                            [  OK  ]
[root@localhost yiyujia]# chkconfig --list | grep -i netw
NetworkManager  0:off 1:off 2:on 3:on 4:on 5:on 6:off
network         0:off 1:off 2:off 3:off 4:off 5:off 6:off
[root@localhost yiyujia]#