Dell D600-i hate this money eater

I have a dell d600 and of course i get the ac adapter message at start up. i bought a new adapter but the thing still says that the adapter isnt recognized. i noticed that the power jack is loose and jiggles to where i can even cut off the computer by moving the cord. is this why i am getting this message or is it something else. Can i replace the power jack my self and if so how (its like 5.00 on ebay).

Thanks in advance for the help