Firstly, let’s fix out the definition of default password. Windows XP has a built-in user account named "Administrator" and by default it is not password protected. If you never set password for this account, you can log on to computer with this admin account. And then you could easily reset lost Windows XP password through Control Panel or Command Prompt.
Knowing the default password would be very useful when your computer prompts you for one you don't know, like the password for the Administrator account. There are a number of situations where having an XP default password would come in handy. For example, if you don't know the Administrator password but you're diagnosing a serious problem and are accessing the Windows XP Recovery Console, the default Administrator password would sure be nice.
There are some situations that you need a default password for Windows XP.
1. I really needed a default Windows XP password so I could get into my account. I completely forgot what I set my password to!"
You don't need a default Windows XP password if you've forgotten yours. There are actually several different things you can do if you forgot your XP password and need back in.
There is no true default password for Windows XP, not for the Administrator account nor for any other account.
While there may not be an actual default XP password, there are other ways to accomplish the things you wanted to get done with a default password:
2. Windows won't start at all so I need to get into Recovery Console to fix the problem but I don't know the Administrator password. I really needed a default XP password so I can get on with fixing this problem!
Every Windows XP computer has an administrator account. You should also know that some other diagnostic areas of Windows XP that seem to require access with the Administrator account actually don't. Your user account can also have administrator privileges which is enough to satisfy the requirement. Safe Mode is a perfect example of this in Windows XP.
Also there are many ways to find or reset Windows XP password with a password hint, Windows password reset disk, an available admin account or a Windows password recovery tool.