I would begin checking you can get to the config page of the router first:
http://192.168.0.1/
Log in and check you are seeing the Network Status as established. Also note your firmware version here (it will come in handy later). If you do not have "established" consistently, troubleshoot with your ISP until you do.
Once you have "established" status, plug your computer into port 1 of the DIR-655 and unplug your VOIP phone for now. See if your internet works. If so, plug your VOIP phone into another port on the DIR-655. If not, respond on this thread.