I hope that you don't think me wrong for correcting you, but you stated that moving your personal or User folders requires thinkering with the REGISTRY.
That is not correct, if you have an additional internal drive or have created a separate partition, the way to move the user / personal folders to that other internal drive or partition is as follows:
Open Windows Explorer,
Expand your C drive by clicking on the arrow sign next to it, or double clicking it.
Find the main directory named - Users
Expand that directory and find your name.
Expand your name - Under will be a list of all the folders you can move.
Right click on top of any of the folders you want to move and on the menu that opens click - Properties.
Each folder will contain a Tab named - Location. ------ WARNING DO NOT MOVE THE DESKTOP FOLDER.
Change the Letter from C to what ever letter your assigned to your other partition or drive - the rest of the path is fine.
Documents - The path is C:\Users\yourname\Documents.
Lets assume that your partition or secondary drive letter is - F
The path will now read - F:\Users\yourname\Documents.
Windows will give you 2 promps, asking if you want to move the folder and 2, informing you that it will be best to avoid duplications to also move all the contents of the folder.
You have to click - Yes to both.
Please understand that the folders although possible, should not be pointed to external drives because if for some reason the drive is not ON, or connected, Windows will NOT be able to find the folders after re-directing them, causing possible error messages.
The WARNING ABOVE about the Desktop Folder - It's necessary for Windows to have that folder on the C partition or you will get error messages.
However, keep in mind that the Desktop Folder only has - Shortcuts to programs, which are easily recreated, so there is really no need to move this folder as its needed by Windows Desktop as soon as the computer boots to the Desktop.
This works for Windows XP as well, except that in Windows XP, the main user / personal folders are under a main directory called - Documents and Settings ( am a bit rusty on Win XP, but is easy to find ) so the folder name am giving above may not be exact.