Water Damage

I've been given an HP dv5000 laptop that will not boot. There was a small amount of water spilled on the laptop's keypad. The computer was turned off immediately but not permitted to dry out before being turned on again. Once on, a slight burning smell was evident, I'm told, but it would not start. About 4 weeks have now gone by. When I now turn on the laptop there is a 2, 3 second whir of the fan, the LED lights glow steady, it sounds as if there is an attempt to boot, then a click. Then everything stops with a black screen and no further sounds.

The computer does not respond to any F-key during the re-start process. I have disconnected the ac adapter (there is no battery), held the power key to drain any residual charge. I have inspected all internal parts for damage (none evident), reseated the CMOS battery, RAM, hard drive, connected a USB keyboard and replaced the AC adapter. No progress. I suspect I'm now due to change out other parts.

How do I determine which part is affected?

All I know about the computer is that it runs Windows XP, 512mb memory, and a Celeron M Processor. No external hardware.

Help is appreciated.