The way you describe the breakdown implies that something has gone wrong and you have not fixed it. You need to identify what that is - hardware or software. Just because the lights are flashing, does not mean that the hardware is operating correctly. I would start by removing the router and checking for a response just through the modem. Perhaps also go-back to an earlier set up via System Restore. See if you can borrow a modem and install that - see if there's any improvement.