Most likely dead motherboard. I would reccomend you attach your HD from your laptop to a desktop and copy all of your important data. Laptops are pretty had to fix if there is an actual motherboard problem.
Agree, you've probably a motherboard issue. However, there are a few tests we can do left.
Do you have a multimeter to check the voltage output on the PSU? You want to make sure that it's good.
Is the DC socket or the cable on the PSU loose? Does wiggling the cable around when it's plugged in let any LEDs turn on?