I have a customer laptop won't power on.

The report from the customer was that he went to plug the power in and put it in the wrong port and he said that he heard some sort of craking noise.

The laptop will not power on doesn't matter if the power cable is in or not.
I have tryed removing the battery for 5 min's.
Removing the RAM
Then Removing the hard drive.
In all cases the it didn't power on,

All that happens when you press the power button is that the light will go on for about 5 seconds and then turn off. There are no beeps. No sign of damage anyway.

The laptop is a dell latitude D600.

If he heard crackling, my guess would be that some part of the laptop's motherboard is fried. Have you opened it up to inspect it yet?

I don't get how you could manage to jam the AC adapter into the wrong port though...

Had a similar problem with a D620 that was given to me (because it would not work) it turned out to be that the CPU was not locked in properly I just turned the locking screw to unlock and back to lock and all is now fine, hope this helps

Remove and reseat the ribbon video cable from the motherboard to the screen... that eliminates another possible cause.
What could he have plugged into the wrong port? The power plug into the modem or ethernet port or USB port?

Remeber to ghost the drive as it could be needed

thanks for your suggestions guys, but it has been deemed that the mobo is fried.