How to Hard Reset TP-LINK Products to Factory Default Settings (Wireless Router)

Suitable for: 300Mbps Wireless N Router,150Mbps Wireless N Router, 54Mbps Wireless G Router

Note: A hard reset will remove all your settings, and your device will be restored to factory default settings. Do not perform a hard reset unless you have backed up your settings or you can do the configuration again.

Directly press and hold the reset button on the rear panel with a pin for approximately 6 to 10 seconds when the device is running, then the device will be reset and reboot automatically.

Note:
1. Make sure the device is powered on before it reboots completely.
2. After the hard reset, the IP address of the device should be change to the default 192.168.1.1, and the default login username and password are both admin (all lower case).
3. Ensure that the IP address of your computer is in the same IP range with the device. That means your computer should have an IP address like 192.168.1.X (X is in range of 2~253), and the subnet mask is 255.255.255.0, the default gateway should be 192.168.1.1 which is the IP address of the device. 

Source: tplink