In Windows Vista, be default the Administrator account is disabled. However, if you use a password reset tool, there is a chance that you can enable this account and cause it to appear on the Welcome Screen. There is an easy way to fix this. From an elevated command prompt (right-click cmd and select "Run as Administrator"), type:
net user Administrator /active:no
If the forward-slash causes you problems, simply enter the same command without it. If you're successful some text should output indicating the command was issued successfully and the Administrator account should disappear form the Welcome Screen and return to its disabled state.
