Yes it will work.
Do some reading on these forums and you'll get answers to your other questions.
And you're not dumb. You're ignorant. Ignorance is curable with education.
I have a fairly high spec (core2duo) Sony Vaio laptop, but the screen is broken (only half display). Would this be useful to use as my car pc and connect to a touchscreen? I amd COMPLETELY NEW to this and have no hardware other than the laptop so please bear with me.
If I could use this, then where do I go from there? It is a 3 series coupe by the way.
Best touchscreen to get?
Adaptors for laptop power supply?
As I said, first visit to website so I am a bit dumb!
You can purchase a 12v power supply for just about all laptops these days. Try a google search for your Vaio model number and power adapter. You should get some results. It is simple to disasemble the cigarette lighter plug, and simply hard wire it into a power wire that comes on the the ignition. One nice thing about using a laptop, is during cranking, the internal battery can sustain the laptop, and keep it from resetting when you start the car.
The next step is to find a touchscreen to use, there are literally hundreds of choices. Most hook to the USB port, and with the supplied drivers, the screen mimics a mouse when you touch it.
That's really all the essential parts to get you going hardware wise, next is to research some of the front ends out there. Centrafuse (a retail product) and Road Runner (open source) are 2 of the most popular and widely used front ends. A front end is really essential, as trying to run standard windows programs with your finger on a small touch screen is virtually impossible