I just wanted to post this information here so you wont have to go far to find it.
When using a Dell M1710 laptop in your car you can take one of two routes to power it up.
The first and most common route is to use a CarNetix CNX-P2140 DC to DC regulator and have that power a secondary adapter that was built for your laptop to be used in a car setup. This secondary adapter is used so your laptop boots up and does not give you an error message saying the adapter can not be identified. The cost of these type of adapters are about $100.
The second way to go about doing this is to use a Carnetix CNX-P2140 DC to DC regulator to power the laptop directly and use the old AC power brick to satisfy the ID check circuit. This method saves you the additional $100.
For details on this second method see my work log (first page)
2003 Honda Civic Hybrid Work Log