The list is far too long to write here, but its rare to find someone that has the skill to not only disassemble the laptop but use meters, oscilloscopes and has the required electronics engineering background to dive into the power sections of a laptop. No offense intended but if you had that background... you wouldn't ask.

--> For such a laptop the common exits are:

1. Make sure the wall power unit works. Hint: Voltmeter.
2. The battery can be removed during test. Tip: A dead battery can not only stop a machine cold but can damage the laptop's charging circuits. I've seen good laptops go sour when the battery should have been tossed. Hint: Unlikely at 2.0 years.
3. If the power brick is good, then its time to search Ebay for a replacement mainboard. Why? There are few that have the skill to repair such. Why? If you ask, then you don't have that skill. Again, no offense intended.

Best of luck,

Bob