I know how to do it! I asked this same question a long time ago.
Download this: http://download.microsoft.com/downlo...ertoySetup.exe
Its Microsoft XP PowerToy called 'TweakUI'. It will do exactly what you want. Now since I'm in Vista i'll have to tell you this by memory.
OK I found a little picture on Google that should tell you how to do this.
So basically you are trying to do an auto-logon?
As for XP Pro x86 & x64, you need a 64-bit CPU for that.
I heard its better to have a 32-bit OS on a 64-bit CPU. That doesn't make very much sense though...