Update your firmware by following the instructions here in the
previous post, as buggy firmware might be the problem. If you already have the latest version of the router’s firmware, use the firmware menu to return all of the features to their default settings. If this solves the connection problem, be sure to make future settings changes one at a time so you’ll know what setting causes trouble if you encounter problems again.

Another way, is to reset your network devices. This gives them the chance to reassign IP addresses and connect to each other without conflicts. To completely reset your network devices, power off your PC and then unplug your broadband modem and router. Leave the units unplugged for a few minutes. Read your device manuals to determine whether you need to perform any additional tasks to reset the devices.

Finally, plug in and power on your devices, starting with the broadband modem, then your router, and then your PC.