Oh lordy, I had to replace one of my hard drives on my old computer. It was a whole weekend of terror ("please don't die, please don't die, what's that clicking sound?") that involved copying everything to a new drive with identical partitions. Windows 7 is actually remarkably hardy when you copy it directly from one disk to another, and I had no issues after the transplant, thank goodness. I did have to run a repair process to get it to like the new boot partition (I think that's what it was after), but then it worked without a hitch.
Also, I've had hard drives fail on me. I wrote a game I called "Steeltech" once, and it was awesome as hell (in my 15/16 year-old mind), a hard sci-fi grim adventure game with a nice system (I don't remember what exactly, but it compared relatively favorably to d20, and I think it used similar dice). I believe I lost that to a hard drive failure, though I may dig it up years from now on a drive that was discarded when a computer died for other reasons. To some degree Orchestra retains a lot of elements I remember from Steeltech, though it's a lot lower on the tech scale.