laptop inverter

Can someone please explain in the simplest terms if I am able to use a car adapter to power my laptop instead of an inverter, and if not why? IF it is a matter of I can't USE the laptop while it is plugged in with the adapter, can I charge it, and then disconnect and use it? Will it be a matter of I'll mess up the laptop, or that it will just take forever to charge? I question this, because I have seen a lot of relatively power hungry "household" things plugged into the lighter socket and work fine, so I'm wondering what is the bug deal with laptops.

I have seeing laptops connected to the car, but there was some other hardware that was between the cord of the laptop and the lighter socket. It was some kind of converted or something. Anyways, that thing had had a socket like a regular indoor power socket in which the cord of the laptop could plug in. I think it was an AC/DC? Converter. It magnified the power or something to 100 watts (120 volts) high enough power to power a laptop (and a TV set). I guess you need an inverter for that. You can buy one in Wal Mart.