Hi, we have cable internet, the service has been going in and out for months now. Bought a new router still having problems. Cable company has been out several times, changed modem, etc. Now hooked up straight to cable with no router, working fine so far, but no wifi , kicks off when router is connected. In the past when router is on it will work for a few hours or even a day or two, then go out.
Get a new network cable to go between the modem and router. Have you checked the router settings for the WAN port? Are they correct? Could be that the new router has not picked up the settings from the modem yet.