I was making a long ethernet cable to go in to my 360 into my room and I didnt put the wires in the plastic end correctly cause i wanted to see how long the cord needed to be. and then the plastic end of the cord didnt fit into my xbox because it was too big so i went down stairs to see if it would fitinto my computer and it did a bit ( the wires were still not properly placed) and now when ever i put my regular ethernet cord into the computer it says its not connected and will not connect me to internet. is it possible the ethernet cable i was making could have messed up the ethernet port because the wires were not properly placed? i dont know someone help please.

Thanks.

If you mean you put a new RJ45 connector (like this) in the PC without pushing the copper connectors onto the wires inside then yes, you could have damaged the inside of your ethernet port.
The connectors have to be pushed into the wires of the cable before you can stick it into a port or else they will stick out too far and will probably bend your ethernet port connectors out of place.