Windows Server 2000/2003 General Support

I have had to re-install Win 2000 as I was having problem with Zone alarm and couldn't connect to the internet.  This problem has gone but I sometimes need to use my dial-up system and this has now stooped.  Win 2K says that I ...

How easy (or otherwise) is it to change my own Windows login name on my on PC where I have full administrator rights? Is it simply a question of changing it under "Users and Passwords", or are there other aspects/complications? ...