[Swordmaker]

Windows XP users have that ability, but many don't bother with entering user/passwords at start up. I have a "guest" account on both my XP machines, and only the "Administrator" can install/uninstall/alter the Windows configuration.

But I bet that 97% of Windows users are operating in full Administrator mode.

[BigSkyFreeper]

They are actually, even those with multiple family accounts.