I've seen a lot of questions asking somewhat the reverse of this question, namely copying games from one PC to another to avoid downloading. My question is can I just remove my entire hard drive from my current PC and move it into the new PC and get Steam to recognize that all the games are already downloaded? I'm basically wondering if the way Steam knows which games are installed is tied to the account info in the cloud, or PC-specific information (like registry entries) or some combination.
The specific example: I have a PC with a C: drive and a Z: drive. 90% of my games are on the Z: drive. My new PC has just a C: drive, and I want to put the Z: drive into the computer and just get Steam to see everything there.