If you hide only the folders in your root drive then the users will still be able to access the files easily enough. Just click start->run and enter c:\windows or c:\program files. Hiding every single file on your computer will make it pretty difficult to use (not to mention might take a while for your computer to do). Your desktops and start menus will be kind of empty. Also, I'm not sure, but I believe that even a limited user account can still set explorer to show hidden files.
The fact of the matter is that hiding files is not very much of a security measure at all. Since it is not a per-user setting, they will be hidden from you too. If those with whom you share the computer can't be trusted to access the hard drive you really shouldn't be sharing a computer with them.
Why are you trying to hide all the files?