By default the administrator and guest account are disabled for security reasons.
This makes it harder for hackers to hack into Vista and also it makes Vista run much more secure by default, for instance when surfing the internet with administrator account disabled and UAC enabled: Vista makes Internet Explorer run in user mode, while XP ran instantly in administrator mode. Running Internet Explorer in administrator mode means that sites are able to run bad programs on the fly without your permission, you can probably imagine this makes your PC very vulnerable.
But if you are running these accounts anyway, and would like to rename them, here is how to do it….
Click start and type secpol.msc
This will open up the Vista Security Policy Editor, now browse to Security Settings, Local Policy, Security Options
At the top double click for both the administrator and guest account, choose enabled. Close all windows and restart Windows Vista.
You are now able to login to Vista as administrator or guest. A good option is to Rename those accounts to make it harder for hackers/friends you don’t trust to find your precious login 
After enabling these accounts you should set a password as well, click start then type in cmd, then type net user administrator “password” without the quotes of course, you can do the same with the guest account or any other accounts, for more info on net user type net user /? or net /?
This does not work for Vista Home Premium.
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To [...]
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To [...]
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To [...]
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To [...]
[...] by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To Geek] Share [...]
[...] At the How-To Geek’s home away from Lifehacker, writer Mysticgeek runs down the process for changing the Guest Account name in Windows 7, which requires a little switch and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. [...]
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To [...]
[...] and name change by an administrator. Want to pull off the same kind of trick in Windows Vista? Try DotNet Wizard’s guide. Rename the Guest Account in Windows 7 for Enhanced Security [the How-To Geek] Kevin Purdy @ [...]
I’m pretty much impressed with the stability of Windows 7. It is better than windows Vista which hogs my memory and cpu.::,
Windows Vista is good but it can hog your CPU and Memory.:,’