MacBook Pro won't power on

Someone brought a MacBook Pro Core 2 Duo to the computer repair shop I work at. Originally they wanted a hard drive upgrade, but it seems to be having other problems. The other technician reported a burning smell when he tried to turn it on. It will stay on for at most 3-5 seconds then shuts off, and every attempt to power it on after that will be even shorter. I know this model has a known-to-fail NVidia GPU, but it seems unrelated to the problem.

If the tech smelled something burning, that should be clue enough to indicate there's a short somewhere. Power supply, logic board, ??? Probably a good idea to notify the customer and pass along the bad news.