green light on Dell ac power adapter goes out when plugged into laptop

So, I decided to pull out my unworking dell E1705 laptop from the closet. I ordered it on 6/21/06. It was originally my grandma's who never used it except for when she went on vacation to florida for one month. SO it was liek never used. Then she passed away so we got the laptop. Well the battery just suddenly stopped working one day. It worked one night then next morning it was deader than a doornail. Then the ac adapter just started to do this. When you plug it into the wall the green light turns on. But once you plug it into my Inspiron E1705 it just goes out and the laptop turns off. But it works on my Inspiron E1505. So I did everything i could think of. took battery out pluged ac adapter in...nothing. Plugged it into the laptop first then plugged into wall.. nothing. no green light whatsoever. But then if i plug it into my E1505 it works like a charm. The computer and ac adapter look sparkling new. They were taken very well care of. It just stinks that I have a $800 computer sitting collecting dust. Is it the internal main bored. And if it is how hard is it to replace. what is it exactly. How do i fix it. How much does it cost. If i were to extend my warranty would it be covered by that? This is just sad that i have a 12 year old sony that works. it at least gives you enough battery power to switch outlets if you wanted to switch rooms. so far dell suck. they nickel and dime you just to call customer service! DELL SUCKS! please help!