can only connect to internet if using a switch

[mrtippmann]

if i plug my Ethernet cord to my computer it will connect saying identifying network then the red x will appear as if i unplugged it then it will says its identifying again and it will keep repeating itself. if i plug in the same wire to a switch and then use another wire and connect that one to my pc it works but why?

 

[AgPaul]

Not sure about your set up but in the old days before auto MDIX (senses the pins and type of device using the port) you had to use a crossover cable to connect directly to a router

 

[mrtippmann]

it was working yesterday but today it wont work