Also, try bypassing the router, setting the modem with the username and password, and seeing if you can go online. This will confirm you username and password. Then turn off PPPoE and all things in your modem (set it to bridge/transparent), disconnect it from the PC and power cycle it.
Next, log into the router, save your configuration (just in case), and do a factory reset. After giving it time to reset, power cycle it again. Then log back in and configure with the same username and password into the router as you did the modem, and **clone the mac address of your computer to the router**. Once all configured, reconnect the router to the modem and power just the router. If your not online then, I would be very confused.