The ol switcharoo
 

I have about 4 boxes that either do not have working hard drives, dvd, etc.....

1 box has bad HD.....Can I take the working HD out of another and put in? If so...What are my steps?

Thanx

You need to unlock the HDD you want to put in (You can only unlock HDD's by using the stock mobo it came with, then boot a program that can unlock it), and the xbox you are putting the HDD into has to be modded.

switching dvd-roms would be the easiest.

Your drive may be able to be saved, but erased in the process. Not for sure though:
http://forums.xbox-scene.com/index.php?showtopic=257895