Breaking The XP Password:

In case of user password boot the pc in safemode by pressing the F8 key and then selecting the Safe Mode option. You can now logon as an administrator and XP wont prompt for the password. Incase of an administrator account try rebooting the pc in DOS. access C:\Windows\system32\config\sam . Rename SAM as SAM.mj
Now XP wont ask for password next time You Login. Also

Go to the cmd prompt .
Type net user *.
It will list all the users.
Again type net user "administrator" or the name of the administrator "name" *.
e.g.: net user aaaaaa *(where aaaaaa is the name).
It will ask for the password.
Type the password and there you are done.
Logging In As Administrator:

Hold the Ctrl-Alt key and press Del twice. This will bring up the normal login and you can log on as Administrator.

To unhide the Administrator account so it does show up:

Start Regedit

Go to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ Winlogon \ SpecialAccounts \ UserList

Unhide the Administrator key by giving it a value of 1