The DC03 is the cylinder vac isn't it. I've done several of these and believe me if you are not into the repair game then you've chosen a beauty to start with. Practically everything needs to come off it. Most of the items clip off, or pull off in some way and most seem as though they wont come off with the amount of force you need to use for something thats only made of plastic. Each of these parts would take a few lines to describe how to take off and what to watch for, and if you break the on/off or cable rewind press you're up a certain creek without a paddle. You need a Torx screwdriver for the screws aswell!
If you're in any doubt whatsoever, don't attempt it.
steveD, April 2008