Ethernet cable doesn't fit in socket
First of all, yes, I'm putting it in the right place. I know which one is the modem socket and which one is for an ethernet cable. I've used this same socket (is that the best word?) for over a year, and it's been fine. Now, however, my ethernet cable keeps coming out of the socket. I can put it in, but it is extremely loose, and comes out every few seconds unless I continually push it in. I was actually content with this, but now it's gotten even worse, where even if I push it in, it often does not work. I especially have trouble accessing anything online where I have to press a button (a yahoo/google search, or submitting any information online such as on an e-mail website. I'm typing this from another computer by the way.
What should I do? Do I need a whole new computer, or is there some way to fix the ethernet cable socket? Alternatively, could I do something to press the cable in and keep it in the right way for good? Thanks a lot for all your help, as this is a very, very frustrating situation.