Is it possible

[Ex.plode]

So if I install it on my second computer, using my own steam account.. I should be able to play LAN as long as we have our internet/wifi button set to off?

 

[Waywocket]

Yes, an ethernet cable will do. Make sure you have the right one (straight, not crossed, if I'm correct).

OT, but in fact it's the other way round: a crossover cable is for connecting two computers directly. In real life it's largely irrelevant though, as any network hardware bought in the last decade or so will be auto-sensing and work with either wiring regardless of whether it's a direct connection or going via a switch.

 

[Louis XXIV]

So if I install it on my second computer, using my own steam account.. I should be able to play LAN as long as we have our internet/wifi button set to off?

Unless it recognizes, through the shared LAN account, that another computer is using it.

Short Answer: Haven't the foggiest idea.