Flickering Router Lights?

So, we live in a rental house, so our internet is wired ethernet. Previously we had no problems, but when we needed to do a reset because of an issue with the local cable internet company, the router has been doing strange things. When I reset it and turned everything back on, all the lights now flicker. I didn't think much of it, but our internet connection goes in and out constantly throughout the day. It does this in all five rooms, so I know it's not any specific cord or ethernet port that's the issue. The internet will work for five minutes and then stop working for five, and repeats this all day and it makes doing anything impossible. It says the connection is there, but it obviously isn't half of the time. I've tried unplugging everything, letting it sit, and plugging it back in, resetting, etc, but it always comes up flickering. Am I resetting the router improperly, is there another issue, or is the router just done for?