Latitude D600 will not turn on

I have a Dell Latitude D600 which will not turn on. The AC adaptor convertor will display a green light when plugged into a wall outlet but not the laptop; the light on the adapter convertor goes out when I plug the adaptor into the computer. I get the same results with the docking station. I have a green light on the docking port's adapter convertor which goes out when I lock the computer into the port. The results are the same with or without the battery installed.

I'm thinking that I need to replace the power supply. However I'm having trouble finding the part number for the power supply so I can track one down.

Can someone help?

Thanks!!