I had a similar problem. My laptop power adaptor was not working, I went in with the laptop, and they sold me one that was not quite a good fit (too much play). They ended up selling me a universal adaptor (generic brand) which is not the right size for my laptop, then tried to tell me I would need to change the jack (for an additional $90). I am not going back. I wish they were honest and simply admitted they did not have the right size.
p.s. I found a brand name adaptor (the right one) at Tech Direct on Kennedy.