I received three of these from a school district. They are core duo, 15" widescreen laptops. The use the traditional four pin, 2.5mm dc jack that many hp, gateway, and others use.
They all had the classic symptom of being able to hold the power cord in just the right way to power up. Once taken apart two of the voltage pins were oxidized and all three needed to be replaced.
After dc jack replacement the laptops power on again!