if everything else works on the laptop, then just go and crack open the laptop and replace the motherboard, taking note on what screws goes where. As you've said, replacement motherboards off ebay and such you can get cheap, and it is easier than going through the trouble of hunting and soldering for a specific part(s).

Fried a working motherboard with charger board.

I had bought a replacement motherboard and fried it right away. I plugged it in with out a monitor hooked up and the fan failed to kick on but the processor did get warm. Then I shut it off and plugged in the board where the battery and HD plug in to and the board had started smoking. A 8 prong rectagle chip at the bottom of the board had fried. If that board that connects the HD and battery was bad could that fry the motherboard. Here is an auction of the board if you don't know what I am talking about. I inspected it and there is no burnt chips or anything. Also, which I had made another thread just to see if this is the problem is that I had the board on a electrostatic bag. Would that conduct electricity and possible fry the board?

http://cgi.ebay.com/Charger-board-for-Presario-1500-900-Evo-N115_W0QQitemZ270180329982QQihZ017QQcategoryZ3666QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

electrostatic bags do not conduct current. If this is the second motherboard that has failed (was the same chip fried on the old one?) then it has to be another component that caused the problem. Anything you connect to the motherboard could be the cause. Without diagnostic kit you are going to struggle to find what it is cheaply.

No the same chip on the other board isn't fried. When I power on the laptop with the board that isn't fried it will power on and you will hear the hard drive run and then it will power off and the fan doesn't turn on. When I plugged in that charger board when I got the replacement board it made a spark at the connection where if plugs into the board and then that chip fried. I tried plugging it in after it smoked and plugged it in and the board made a beeping noise that got higher and higher then I shut it off. I noticed the intel chipset(not cpu) had gotten really hot.