Regedit.exe & XP

I am currently researching how to lock down the computers
in our firm. When I review literature on using Regedit
for XP it states to use the Permission option within
Regedit. For some reason I ds not have that option. Is
there an updated version of Regedit? I have also checked
other PC's in our office and they do not seem to have
this funtionality.

I know that on our Win 2003 Servers, the permission
option is availabe.

Thank you in advance.