Generally, as we cannot determine the intentions of having this knowledge, we cannot disclose this information.
Hope this helps!
Didn’t think of that… bottom line is we need more information.
If you are asking how to access the default administarative account in a Microsoft OS, then support.microsoft.com or technet.microsoft.com has articles on how enable or access the local administrative account for Windows XP and Vista. For a specific answer, see above.