it all depends on your console "slim or phat" and drive inside, "liteon, sham, benq and hitmachi". All you need really in your PC is a Sata port, If you want do it professionally you can pay money and buy hardware to make any PC be able flash your Console but for the cheapest way, If you have a Hit or sham, then its has simple and using your console to power your drive, and have the sata port into your PC and not xbox.. The benq is also very easy but the Liteon needs a probe get the key...
Your Key is whats marries your drive and motherboard on xbox, if these key's don't match then your console wont play games, so your key is an amazing and very important thing backup..
If your interested in flashing download JungleFlasher and go into Documents Folder and open JFtut.pdf, This explains everything, Just scroll down and click the Xbox image that you have, then choose drive and follow instructions