I have a question about my laptop charging unit!!?

I have a Dell 1501 laptop and I'm not sure but I think the adapter in the back of the computer where the charging cable goes is a little broken or something....I used a Electric tester to see if the computer was getting any power past the cable....The tester said that the computer was getting power its just that the battery led was not lighting up and the computer would not come on....Now if I push the power cable really hard, in and up, I get the green led meaning the battery is charging and I can start the computer...but the minute I let go of the pressure the computer will loose power and turn off (duh).....I have tried using a different cable adapter the same as my model and still the same thing...I even went as far as to take apart the whole computer and look at where the cable input adapter goes on the motherboard just to see if some of the solder was broken...and still nothing...I have spent my whole weekend working on this computer..I just got done reinstalling vista and then the power adapter craps out...I'm getting what you call a little frustrated....any help is greatly appreciated...thanks for your time...