Gutting my old laptop to build a briefcase computer

[BrrDee]

Hello,

I currently own a Dell XPS L501x Laptop (specs below). Recently the discreet graphics card stopped working and can no longer run many of my games without major struggle.
I decided I would like to cheaply and effectively build a briefcase computer and would like to know what components I can likely use from my current laptop (so long as I do screw them up taking it apart ) I'm fairly new to this world, so be gentle kind souls. If you need any other info let me know!

Processor Intel Core i5-560M @ 2.67GHz
RAM 4GB
Graphics NVIDIA GeForce GTX 420M 1GB - crapped out
Operating System Windows 10 Home Premium 64-bit

Also, If I build the box myself, these are some rough sketches I was thinking regarding layout:

http://imgur.com/FcWrnLL

 

[KevinS200]

Motherboard,CPU,RAM, & Another Graphics Card if the other one doesn't work anymore
Also the Hard Drive. Pretty much all the stuff you need too make a computer.

 

[unksol]

The point of a briefcase computer is to use upgradable desktop hardware that will be more powerful and cheaper than a laptop at the cost of bulk. You laptop still works. It's much smaller than a briefcase. You can't add a GPU even if you disassemble it. So all you could do is stick your laptop in a briefcase. Which would be pretty silly. It would also make it extremely fragile if you took it out if it's case and screw up the cooling. Basically the only think you could use is the hard drive