|test the following:|
switch power supply with another one of same voltage and same connector
... try to boot
use current power supply and remove battery ... try to boot
If all the above fails, its your motherboard that went bad. Three years
old is ancient for a laptop. Motherboards can go bad within a few weeks of
purchase and when out of warranty ... at anytime!
Search Ebay for a new or used (working) motherboard from a GOOD seller. Install it yourself and save $.