I want to install HG510 provied by mtnl

You have to take a pen and hit the reset button, and hold in on it for about thirty seconds to minute. Be sure to re-secure your wireless internet after that, so your neighbors can't use it, by using a personal password. It is located under basic wireless setup on the router page. 192.168.1.100 is the default after the reset of linksys been pressed.