Sony VAIO GRT915M power problem

Hi,

I have a 2nd older laptop (the above model) which doesn’t power up. I assumed it was a faulty PSU so bought a replacement. It didn’t help so it must be a problem inside the laptop. The power port seems a little loose. As this laptop is now a little old I am wondering the following:

  1. what the problem could be
  2. would it be cost effective to repair it as I want to sell it

Obviously it’s moe attractive to buy working but I don’t want to spend silly money on it when it’s not worth it.

Any help would be appreciated.