Laptops aren't ATX-compliant, so you can't use it the way it was meant to be used.
IF the power prick outputs 12vDC, you could use an ATX unit to output the 12v, but it's a kluugey solution. I wouldn't recommend it, but others have done it.
Check the output voltage of the power brick. Its likely the necessary voltage can be provided by one of the Carnetix regulators.
And here's a good read for you: http://www.mp3car.com/vbulletin/advf...iew&advfaqid=6