How to reset factory defaults to CK31? How I can put the settings to access WPA2 in wireless network?

Press and hold the pinhole RESET button at the back of the router with the power ON for 20 secs. then release the RESET button.
To connect to your wireless router. the router's wireless settings needs to be configured with the SSID, encryption etc. and also the wireless cards in all the laptops-computers needs to be configured with these router's wireless settings. Then the laptops-desktop computers can communicate with your wireless router.
Connect a LAN cable from the Linksys to the LAN port on your computer.
Open a browser and enter the Linksys configuration URL
http://192.168.1.1
The default login = admin
The default PW = admin
You can protect your router by changing the default admin PW (write it down and put it in a safe place)
Go to the wireless configuration and set up the SSID and WPA or WPA2 encryption to protect your wireless network and Internet from unauthorized access.
Now apply these settings to the wireless card in your laptop-computer.
To secure your wireless network from unauthorized access, please click on this link and follow my instructions :-
http://www.fixya.com/support/r3559128-wireless_router_security

Try resetting the wireless router back to to factory defaults.
To reset the Linksys back to the default settings -
Press and hold the pinhole RESET button at the back of the router with the power ON for 20 secs. then release the RESET button.
To connect to your wireless router, the router's wireless settings needs to be configured with the SSID, encryption etc. and also the wireless cards in all the laptops/computers needs to be configured with these router's wireless settings. Then the laptops/desktop computers can communicate with your wireless router.
Connect a LAN cable from the Linksys to the LAN port on your computer.
Open a browser and enter the Linksys configuration URL
http://192.168.1.1
The default login = admin
The default PW = admin
You can protect your router by changing the default admin PW (write it down and put it in a safe place)
Go to the wireless configuration and set up the SSID and WPA or WPA2 encryption to protect your wireless network and Internet from unauthorized access.
Now apply these settings to the wireless card in your laptop/computer.
To secure your wireless network from unauthorized access, please click on this link and follow my instructions :-
http://www.fixya.com/support/r3559128-wireless_router_security

Most wireless routers have a RESET button to restore the wireless back to the factory defaults then you can configure the wireless setting (SSID and WPA or WPA2 encryption setting).
To secure your wireless network from unauthorized access, please click on this link and follow my instructions :- http://www.fixya.com/support/r3559128-wireless_router_security

Reset the Netgear back to the factory defaults to remove the password.
To RESET the Netgear, power up the Netgear then press and hold the RESET button at the back of the router until all the LEDs flash. Connect a LAN cable from the Netgear to the LAN port on your computer, open a browser and enter the Netgear configuration URL -
http://192.168.0.1
The default login = admin
The default PW = password You can now change the default admin password and configure the wireless settings.
Go to the wireless configuration and set up the SSID and WPA or WPA2 encryption.
Now apply these settings to the wireless card in your laptop/computer.
To secure your wireless network from unauthorized access, please click on this link and follow my instructions :- http://www.fixya.com/support/r3559128-wireless_router_security

How to View or Change Your Wireless Network Password


Symptoms:


You have lost or forgotten the password to your wireless network
You have lost or forgotten the password for the router, access point or other network device
You left the default password or used a weak password and someone has hijacked your network



Depending on the router, you can either view or reset the wireless network password (also referred to as the passphrase or security key) if you can log into the router. Some routers mask the wireless network password, so while you cannot recover it, you can enter and save a new password.


If you cannot log into your router because you have forgotten the router password or your network has been hijacked, please refer to "Lost or forgotten password for router or other device" below.


To view or reset a wireless network password:


Launch your Internet browser and type http://www.routerlogin.net in or http://192.168.1.1 or http://192.168.0.1 the address field for your browser. Enter the router's username and password.
The default username is admin, the default password is password.
From the left-hand navigation menu of the Router administration interface, select Set Up > Wireless Settings
Note: On some routers this option will be under BASIC > Wireless.
From the center screen, you find the current wireless security settings under the Security Options heading.


If the wireless network passphrase is visible, review it and use it to log devices onto your network.
If it is not visible, you can change your wireless passphrase; however, changing the passphrase will cause you to lose your wireless connection. Connect your computer to the router with an Ethernet cable before entering a new passphrase into the text box and clicking Apply.


Read more about Securing your Wireless Network.
If you cannot log into your router:


- If you were routed to the NETGEAR website or getting the "Page cannot be displayed" message when trying to login to router, make sure you are connected to the NETGEAR router. Check your wired connection and make sure cable is securely plugged in and LED is on. If wireless adapter is on, make sure you are NOT connected on a different wireless network.


- Unfortunately, there is no way to recover a lost or forgotten password from a router or access point; you will need to reset the device to factory defaults. However, once the device is reset to factory defaults, you can use the default access information to reconfigure your router settings. NOTE: Restoring factory defaults on a device will erase any customizations you have made. You will lose any configurations saved to the device!


See the following articles for more information:


Secure Your Wireless Network: WPA/WPA2 (Recommended)
Reset and Restore a NETGEAR device to Factory Default Settings
Default Password for NETGEAR devices

If you need to reset this Netgear back to the factory defaults then to RESET the Netgear, power up the Netgear then press and hold the RESET button at the back of the router until all the LEDs flash.

THEN

Connect a LAN cable from the Netgear to the LAN port on your computer, open a browser and enter the Netgear configuration URL -
http://192.168.0.1
The default login = admin
The default PW = password

You can now change the default admin password and configure the wireless settings.
Go to the wireless configuration and set up the SSID and WPA or WPA2 encryption.
Apply these settings to the wireless card in your laptop/computer.
To secure your wireless network from unauthorized access, please click on this link and follow my instructions :-

http://www.fixya.com/support/r3559128-wireless_router_security

Sorry but this is the only to reset the password

Press the Reset Button for approximately 10 seconds

Resetting the Router will erase all of your settings (WEP Encryption, Wireless and LAN settings, etc.) and replace them with the factory defaults.

If you have changed the default password, you need to reset the router to the factory settings to get in with the default user and password (user admin and password as password, or if that doesn't work try 1234 - these are the default password for NetGear routers). Note that you will lose the ISP settings and wireless settings when you reset the router.

Here's a video on how to reset the router to the factory default settings: http://kbserver.netgear.com/media/flash/training/Troubleshooting/NG_WGR614V9Router_TS_LostPassword.html

Unfortunately, there is no way to recover a lost or forgotten password from a router or access point; you will need to reset the device to factory defaults. However, once the device is reset to factory defaults, you can use the default username ("admin") and password (either "password" or "1234" depending on your router) to reconfigure your router settings.

or

if there is a small hole in the front or back of the router push a hair pin in to reset to factory settings

dont forget to vote hope this helps

I'd suggest that you reset the Router to its default factory settings. After doing so, when opening a browser, you should be prompted to initiate the setup wizard. Once set up I recommend checking for any recent firmware updates.


On the WRT120 the Reset button is located on the
right side of the product label. There are two
ways to reset the Router to its factory defaults.
a) Either press and hold the Reset button for
approximately five seconds.
b) Log into your router and restore the
defaults from the (Administration > Factory
Defaults) screen of the Router’s browser‑based
utility.


Check out the Linksys Support Page for your router.

I hope this helps!
Good luck and Please rate :)