You imagine that because you replace parts in Dells, that all Dell computers are the same, your are completely wrong. You know that the power supplies can be unique? At least you have one clue out of 100, not bad.
No, I didn't imagine replacing parts in Dells. I worked in IT for a large software company that had thousands of Dells. Not once did I ever find a Dell proprietary hard drive. I don't know where you're getting your info but you need to quit spreading FUD. Keep up the insults and you'll have a weeks vacation from the forums.