Ethernet doesn't work, but sometimes it magically does.

[Joe Jackman]

Like right now i am using a dongle to connect to wifi, my PC says i have not connected the ethernet cable( but its there). i tired reconnecting the cable from both ends,
https://www.quora.com/Why-is-the-LAN-port-on-my-motherboard-not-working I tired what rohit told me (expect for the antivirus and firewall disabling thing). But strangely enough, when i game at night, my PC just switches to the Lan port and gets connected..IDK if this is a motherboard issue (bought it about an year ago) or my cable (but then it should just reconnect on its own), my router works caz i got like 9 devices running off of it. IDK i should call in the ISP guys for a check, see if the problem is in the cable(i have a cat 4 cable running from my router, optic fiber connection) but if its the motherboard.. 
I need to know if i am missing something here, before i go do those.. TIA