1.拔掉交换机的电源线
2。用超级终端和控制线连到交换机，超级终端的设置是：
9600 baud rate
No parity
8 data bits
1 stop bit
No flow control
3。按住交换机前面板的“mode”按钮，插上电源线，当端口1上面的灯不亮后，放松“mode”按钮；
4。这时超级终端上应该显示：
The system has been interrupted prior to initializing the flash file system.
The following commands will initialize the flash file system, and finish loading
the operating system software:
flash_init
load_helper
boot
5。输入flash_init
6。输入load_helper
7. 输入dir flash:
这时显示：
Directory of flash:
2 -rwx 843947 Mar 01 1993 00:02:18 C2900XL-h-mz-112.8-SA
4 drwx 3776 Mar 01 1993 01:23:24 Html
66 -rwx 130 Jan 01 1970 00:01:19 env_vars
68 -rwx 1296 Mar 01 1993 06:55:51 config.text
1728000 bytes total (456704 bytes free)
8。输入rename flash:config.text flash:config.old
9.输入boot，重新启动系统
10。系统启动完后显示：Continue with the configuration dialog? [yes/no] :
输入N
11.输入enable
12.进入enable模式后，输入rename flash:config.old flash:config.text
13。接着按以下步骤操作：
Switch# copy flash:config.text system:running-config
Source filename [config.text]? (press Return)
Destination filename [running-config]? (press Return)
14 。接着按以下步骤操作：
switch#configure terminal
switch(config)#no enable secret
switch(config)#no enable passWord
switch(config)#exit
switch#write memory
这时,系统就恢复没有密码的状态了