HOW CAN I RESTORE THE FACTORY DEFAULTS FOR MY CISCO ROUTER?

You’ll need a console cable. This is the blue serial cable which should have come with your router. Plug the cable into your router’s console port, and into an available serial port on your PC. Use a terminal program such as Hyperterminal. Typically your port will be COM1: with the settings of 9600 bps, 8 databits, 1 stopbit, and no parity.
Start with the power off on your router. Then, as your turn your router on immediately press -BREAK several times. You should receive a prompt similar to “rommon>”
Once you receive the rommon prompt type confreg and press Enter. There should be an option similar to “Ignore System Config” which you want to change to “Y”. Once this is done (and you cycle through the rest of the settings) simply type boot.
When the router boots it will ask if you want to enter the initial configuration. Say no. When you get to the router> prompt type:
enable
wr erase
config t
config-register 0×2102
exit
reload
When it asks if you want to save the settings say no, then press Enter.

Robert is right there is button where a pen is used to press the button down for 3-5 second. Then you must unplug and replug the router. It will go to the default settings. Put in the installation CD and follow the instructions. If your advance type 192.186.1.1 leave the first box blank then type: admin
Note: just unplugging the router will not work. The button must be pressed.

If it is a router, just go to a command line on the device, type “write erase” and hit enter. Then type “write mem” and hit enter. Lastly reboot it, you will be at the as shipped configuration pretty much at that point.

it should have a small reset you can push with a pin tip

unplug it