Pc Doesn't Recognize Ssd

I recently bought a Nighthawk R7000 router modem and whenever I would use ethernet connection on my desktop it would disconnect for a few seconds and reconnect every couple of minutes. I contacted support and they told me to get a replacement, which I did, I went with the R7000 Wifi Router and I am still having the same issue. Ethernet works well on my PS4 but doesnt on my desktop. Any help would be appreciated.