Resetting your Comcast router restores its default settings, which is especially helpful if you forgot your router's password. This erases any changes you made to the router, including its IP address, administrative password and wireless security key. As such, resetting your router should be considered a last resort. If you are merely experiencing connectivity issues, rebooting the router by powering it off should be tried first.
Straighten a paper clip.
Push the paper clip into the reset hole, located in the back of your router, to press the recessed reset button. Hold it there for 10 to 20 seconds, depending on your router.
Release the reset button and wait a minute for the router to reboot.
Restart the computers to restore Internet access. This may not be necessary on some computers.
If the router does not reset, try unplugging the router, depressing the reset button and then plugging it back in. Hold the reset button for 20 seconds and wait for the router to reboot.