Given your experience level with PC gaming you would probably be better off purchasing a used Xbox 360 rather then trying to find a old original Xbox, or original game discs. Seeing as you can download both games off of the Xbox Live Marketplace. I have had some issues playing the PC version. Specifically newer drivers for my graphics card for whatever reason caused the game to lock up, and the only way to resolve the problem was to actually install much earlier drivers onto my system.
Hopefully that wouldn't be a issue for you, but if that ends up being the case it can be a real chore tracking down the driver especially for such a old game. That all said you should also be mindful of the fact that this particular developer isn't known for its great technical skills. Even Mass Effect had a lot of non hardware related issues, and at least Knights of the Old Republic was no different. The game is going to lag out on you on occasion, and the load times are going to be on the long side.
P.S. Even though Knights of the Old Republic 2 wasn't made by Bioware. If you like the first game you will likely enjoy the second game.







