Mac, great stuff!
Cheerio, just to clarify:
In order to maintain access control on files and folders and support limited accounts, you must use NTFS. If you use FAT32, all users will have access to all files on your hard drive, regardless of their account type (administrator, limited, or standard.)
So you REALLY, REALLY NEED NTFS!!
Also, you shouldn't need to go into Safe mode to access the administrator account, but this may be a "feature" of Fast User Switching
, and the Welcome Login Screen. Go to Control panel, untick the Use the Welcome screen and Fast User Switching - that will force all users to enter a username and password - you can even set this so that it is always blank - i.e. doesn't show the last login ID.
There is a wealth of (reasonably) accessible information on Windows XP
here, on the MS XP product documentation site - have a look at the security section
Cheers
SD