Win2K "Users" cannot modify the registry in any way ... not even their own registry.
For some reason MS made the "Power User" in Win2K the equivalent of a "User" in NT4. Win2K's "User" is barely more capable than "Guest."
So, if you make any accounts on your Win2K box, you should make them "Power User" accounts. Otherwise, simple stuff like IE, Netscape, or even Notepad may not even run.
-SUO