I am assuming you unplugged all connections from the router? A little more information would help solve this issue. What modem are you using? Is it leased or did you purchase it? Is this happening in all rooms in your home? Does it affect all devices in your home?
Please answer as many of these questions as possible and I will help in any way possible.
Start here: troubleshooting guide. If you still need help, please post your equipment details (make/model of your modem/gateway/router) and a screenshot of your signal levels and your error/event log. Thank you!